fix(tests): add missing test imports for session/prompt history features

Add missing imports to test module:
- PromptHistoryEntry, render_prompt_history_report, parse_history_count
- parse_export_args, render_session_markdown
- summarize_tool_payload_for_markdown, short_tool_id

Fixes test compilation errors introduced by new session and export
features from batch 5/6 work.

ROADMAP.md

@@ -312,6 +312,23 @@ Priority order: P0 = blocks CI/green state, P1 = blocks integration wiring, P2 =
 23. **`doctor --output-format json` check-level structure gap** — **done**: `claw doctor --output-format json` now keeps the human-readable `message`/`report` while also emitting structured per-check diagnostics (`name`, `status`, `summary`, `details`, plus typed fields like workspace paths and sandbox fallback data), with regression coverage in `output_format_contract.rs`.
 24. **Plugin lifecycle init/shutdown test flakes under workspace-parallel execution** — dogfooding surfaced that `build_runtime_runs_plugin_lifecycle_init_and_shutdown` can fail under `cargo test --workspace` while passing in isolation because sibling tests race on tempdir-backed shell init script paths. This is test brittleness rather than a code-path regression, but it still destabilizes CI confidence and wastes diagnosis cycles. **Action:** isolate temp resources per test robustly (unique dirs + no shared cwd assumptions), audit cleanup timing, and add a regression guard so the plugin lifecycle test remains stable under parallel workspace execution.
 26. **Resumed local-command JSON parity gap** — **done**: direct `claw --output-format json` already had structured renderers for `sandbox`, `mcp`, `skills`, `version`, and `init`, but resumed `claw --output-format json --resume <session> /…` paths still fell back to prose because resumed slash dispatch only emitted JSON for `/status`. Resumed `/sandbox`, `/mcp`, `/skills`, `/version`, and `/init` now reuse the same JSON envelopes as their direct CLI counterparts, with regression coverage in `rust/crates/rusty-claude-cli/tests/resume_slash_commands.rs` and `rust/crates/rusty-claude-cli/tests/output_format_contract.rs`.
+
+41. **Phantom completions root cause: global session store has no per-worktree isolation** —
+
+    **Root cause.** The session store under `~/.local/share/opencode` is global to the host. Every `opencode serve` instance — including the parallel lane workers spawned per worktree — reads and writes the same on-disk session directory. Sessions are keyed only by id and timestamp, not by the workspace they were created in, so there is no structural barrier between a session created in worktree `/tmp/b4-phantom-diag` and one created in `/tmp/b4-omc-flat`. Whichever serve instance picks up a given session id can drive it from whatever CWD that serve happens to be running in.
+
+    **Impact.** Parallel lanes silently cross wires. A lane reports a clean run — file edits, builds, tests — and the orchestrator marks the lane green, but the writes were applied against another worktree's CWD because a sibling `opencode serve` won the session race. The originating worktree shows no diff, the *other* worktree gains unexplained edits, and downstream consumers (clawhip lane events, PR pushes, merge gates) treat the empty originator as a successful no-op. These are the "phantom completions" we keep chasing: success messaging without any landed changes in the lane that claimed them, plus stray edits in unrelated lanes whose own runs never touched those files. Because the report path is happy, retries and recovery recipes never fire, so the lane silently wedges until a human notices the diff is empty.
+
+    **Proposed fix.** Bind every session to its workspace root + branch at creation time and refuse to drive it from any other CWD.
+
+    - At session creation, capture the canonical workspace root (resolved git worktree path) and the active branch and persist them on the session record.
+    - On every load (`opencode serve`, slash-command resume, lane recovery), validate that the current process CWD matches the persisted workspace root before any tool with side effects (file_ops, bash, git) is allowed to run. Mismatches surface as a typed `WorkspaceMismatch` failure class instead of silently writing to the wrong tree.
+    - Namespace the on-disk session path under the workspace fingerprint (e.g. `<session_store>/<workspace_hash>/<session_id>`) so two parallel `opencode serve` instances physically cannot collide on the same session id.
+    - Forks inherit the parent's workspace root by default; an explicit re-bind is required to move a session to a new worktree, and that re-bind is itself recorded as a structured event so the orchestrator can audit cross-worktree handoffs.
+    - Surface a `branch.workspace_mismatch` lane event so clawhip stops counting wrong-CWD writes as lane completions.
+
+    **Status.** A `workspace_root` field has been added to `Session` in `rust/crates/runtime/src/session.rs` (with builder, accessor, JSON + JSONL round-trip, fork inheritance, and given/when/then test coverage in `persists_workspace_root_round_trip_and_forks_inherit_it`). The CWD validation, the namespaced on-disk path, and the `branch.workspace_mismatch` lane event are still outstanding and tracked under this item.
+
 **P3 — Swarm efficiency**
 13. Swarm branch-lock protocol — **done**: `branch_lock::detect_branch_lock_collisions()` now detects same-branch/same-scope and nested-module collisions before parallel lanes drift into duplicate implementation
 14. Commit provenance / worktree-aware push events — **done**: lane event provenance now includes branch/worktree/superseded/canonical lineage metadata, and manifest persistence de-dupes superseded commit events before downstream consumers render them

USAGE.md

@@ -109,6 +109,157 @@ cd rust
 ./target/debug/claw logout
 ```
 
+## Local Models
+
+`claw` can talk to local servers and provider gateways through either Anthropic-compatible or OpenAI-compatible endpoints. Use `ANTHROPIC_BASE_URL` with `ANTHROPIC_AUTH_TOKEN` for Anthropic-compatible services, or `OPENAI_BASE_URL` with `OPENAI_API_KEY` for OpenAI-compatible services. OAuth is Anthropic-only, so when `OPENAI_BASE_URL` is set you should use API-key style auth instead of `claw login`.
+
+### Anthropic-compatible endpoint
+
+```bash
+export ANTHROPIC_BASE_URL="http://127.0.0.1:8080"
+export ANTHROPIC_AUTH_TOKEN="local-dev-token"
+
+cd rust
+./target/debug/claw --model "claude-sonnet-4-6" prompt "reply with the word ready"
+```
+
+### OpenAI-compatible endpoint
+
+```bash
+export OPENAI_BASE_URL="http://127.0.0.1:8000/v1"
+export OPENAI_API_KEY="local-dev-token"
+
+cd rust
+./target/debug/claw --model "qwen2.5-coder" prompt "reply with the word ready"
+```
+
+### Ollama
+
+```bash
+export OPENAI_BASE_URL="http://127.0.0.1:11434/v1"
+unset OPENAI_API_KEY
+
+cd rust
+./target/debug/claw --model "llama3.2" prompt "summarize this repository in one sentence"
+```
+
+### OpenRouter
+
+```bash
+export OPENAI_BASE_URL="https://openrouter.ai/api/v1"
+export OPENAI_API_KEY="sk-or-v1-..."
+
+cd rust
+./target/debug/claw --model "openai/gpt-4.1-mini" prompt "summarize this repository in one sentence"
+```
+
+## Supported Providers & Models
+
+`claw` has three built-in provider backends. The provider is selected automatically based on the model name, falling back to whichever credential is present in the environment.
+
+### Provider matrix
+
+| Provider | Protocol | Auth env var(s) | Base URL env var | Default base URL |
+|---|---|---|---|---|
+| **Anthropic** (direct) | Anthropic Messages API | `ANTHROPIC_API_KEY` or `ANTHROPIC_AUTH_TOKEN` or OAuth (`claw login`) | `ANTHROPIC_BASE_URL` | `https://api.anthropic.com` |
+| **xAI** | OpenAI-compatible | `XAI_API_KEY` | `XAI_BASE_URL` | `https://api.x.ai/v1` |
+| **OpenAI-compatible** | OpenAI Chat Completions | `OPENAI_API_KEY` | `OPENAI_BASE_URL` | `https://api.openai.com/v1` |
+
+The OpenAI-compatible backend also serves as the gateway for **OpenRouter**, **Ollama**, and any other service that speaks the OpenAI `/v1/chat/completions` wire format — just point `OPENAI_BASE_URL` at the service.
+
+### Tested models and aliases
+
+These are the models registered in the built-in alias table with known token limits:
+
+| Alias | Resolved model name | Provider | Max output tokens | Context window |
+|---|---|---|---|---|
+| `opus` | `claude-opus-4-6` | Anthropic | 32 000 | 200 000 |
+| `sonnet` | `claude-sonnet-4-6` | Anthropic | 64 000 | 200 000 |
+| `haiku` | `claude-haiku-4-5-20251213` | Anthropic | 64 000 | 200 000 |
+| `grok` / `grok-3` | `grok-3` | xAI | 64 000 | 131 072 |
+| `grok-mini` / `grok-3-mini` | `grok-3-mini` | xAI | 64 000 | 131 072 |
+| `grok-2` | `grok-2` | xAI | — | — |
+
+Any model name that does not match an alias is passed through verbatim. This is how you use OpenRouter model slugs (`openai/gpt-4.1-mini`), Ollama tags (`llama3.2`), or full Anthropic model IDs (`claude-sonnet-4-20250514`).
+
+### User-defined aliases
+
+You can add custom aliases in any settings file (`~/.claw/settings.json`, `.claw/settings.json`, or `.claw/settings.local.json`):
+
+```json
+{
+  "aliases": {
+    "fast": "claude-haiku-4-5-20251213",
+    "smart": "claude-opus-4-6",
+    "cheap": "grok-3-mini"
+  }
+}
+```
+
+Local project settings override user-level settings. Aliases resolve through the built-in table, so `"fast": "haiku"` also works.
+
+### How provider detection works
+
+1. If the resolved model name starts with `claude` → Anthropic.
+2. If it starts with `grok` → xAI.
+3. Otherwise, `claw` checks which credential is set: `ANTHROPIC_API_KEY`/`ANTHROPIC_AUTH_TOKEN` first, then `OPENAI_API_KEY`, then `XAI_API_KEY`.
+4. If nothing matches, it defaults to Anthropic.
+
+## FAQ
+
+### What about Codex?
+
+The name "codex" appears in the Claw Code ecosystem but it does **not** refer to OpenAI Codex (the code-generation model). Here is what it means in this project:
+
+- **`oh-my-codex` (OmX)** is the workflow and plugin layer that sits on top of `claw`. It provides planning modes, parallel multi-agent execution, notification routing, and other automation features. See [PHILOSOPHY.md](./PHILOSOPHY.md) and the [oh-my-codex repo](https://github.com/Yeachan-Heo/oh-my-codex).
+- **`.codex/` directories** (e.g. `.codex/skills`, `.codex/agents`, `.codex/commands`) are legacy lookup paths that `claw` still scans alongside the primary `.claw/` directories.
+- **`CODEX_HOME`** is an optional environment variable that points to a custom root for user-level skill and command lookups.
+
+`claw` does **not** support OpenAI Codex sessions, the Codex CLI, or Codex session import/export. If you need to use OpenAI models (like GPT-4.1), configure the OpenAI-compatible provider as shown above in the [OpenAI-compatible endpoint](#openai-compatible-endpoint) and [OpenRouter](#openrouter) sections.
+
+## HTTP proxy support
+
+`claw` honours the standard `HTTP_PROXY`, `HTTPS_PROXY`, and `NO_PROXY` environment variables (both upper- and lower-case spellings are accepted) when issuing outbound requests to Anthropic, OpenAI-, and xAI-compatible endpoints. Set them before launching the CLI and the underlying `reqwest` client will be configured automatically.
+
+### Environment variables
+
+```bash
+export HTTPS_PROXY="http://proxy.corp.example:3128"
+export HTTP_PROXY="http://proxy.corp.example:3128"
+export NO_PROXY="localhost,127.0.0.1,.corp.example"
+
+cd rust
+./target/debug/claw prompt "hello via the corporate proxy"
+```
+
+### Programmatic `proxy_url` config option
+
+As an alternative to per-scheme environment variables, the `ProxyConfig` type exposes a `proxy_url` field that acts as a single catch-all proxy for both HTTP and HTTPS traffic. When `proxy_url` is set it takes precedence over the separate `http_proxy` and `https_proxy` fields.
+
+```rust
+use api::{build_http_client_with, ProxyConfig};
+
+// From a single unified URL (config file, CLI flag, etc.)
+let config = ProxyConfig::from_proxy_url("http://proxy.corp.example:3128");
+let client = build_http_client_with(&config).expect("proxy client");
+
+// Or set the field directly alongside NO_PROXY
+let config = ProxyConfig {
+    proxy_url: Some("http://proxy.corp.example:3128".to_string()),
+    no_proxy: Some("localhost,127.0.0.1".to_string()),
+    ..ProxyConfig::default()
+};
+let client = build_http_client_with(&config).expect("proxy client");
+```
+
+### Notes
+
+- When both `HTTPS_PROXY` and `HTTP_PROXY` are set, the secure proxy applies to `https://` URLs and the plain proxy applies to `http://` URLs.
+- `proxy_url` is a unified alternative: when set, it applies to both `http://` and `https://` destinations, overriding the per-scheme fields.
+- `NO_PROXY` accepts a comma-separated list of host suffixes (for example `.corp.example`) and IP literals.
+- Empty values are treated as unset, so leaving `HTTPS_PROXY=""` in your shell will not enable a proxy.
+- If a proxy URL cannot be parsed, `claw` falls back to a direct (no-proxy) client so existing workflows keep working; double-check the URL if you expected the request to be tunnelled.
+
 ## Common operational commands
 
 ```bash

install.sh

@@ -0,0 +1,394 @@
+#!/usr/bin/env bash
+# Claw Code installer
+#
+# Detects the host OS, verifies the Rust toolchain (rustc + cargo),
+# builds the `claw` binary from the `rust/` workspace, and runs a
+# post-install verification step. Supports Linux, macOS, and WSL.
+#
+# Usage:
+#   ./install.sh                # debug build (fast, default)
+#   ./install.sh --release      # optimized release build
+#   ./install.sh --no-verify    # skip post-install verification
+#   ./install.sh --help         # print usage
+#
+# Environment overrides:
+#   CLAW_BUILD_PROFILE=debug|release   same as --release toggle
+#   CLAW_SKIP_VERIFY=1                 same as --no-verify
+
+set -euo pipefail
+
+# ---------------------------------------------------------------------------
+# Pretty printing
+# ---------------------------------------------------------------------------
+
+if [ -t 1 ] && command -v tput >/dev/null 2>&1 && [ "$(tput colors 2>/dev/null || echo 0)" -ge 8 ]; then
+    COLOR_RESET="$(tput sgr0)"
+    COLOR_BOLD="$(tput bold)"
+    COLOR_DIM="$(tput dim)"
+    COLOR_RED="$(tput setaf 1)"
+    COLOR_GREEN="$(tput setaf 2)"
+    COLOR_YELLOW="$(tput setaf 3)"
+    COLOR_BLUE="$(tput setaf 4)"
+    COLOR_CYAN="$(tput setaf 6)"
+else
+    COLOR_RESET=""
+    COLOR_BOLD=""
+    COLOR_DIM=""
+    COLOR_RED=""
+    COLOR_GREEN=""
+    COLOR_YELLOW=""
+    COLOR_BLUE=""
+    COLOR_CYAN=""
+fi
+
+CURRENT_STEP=0
+TOTAL_STEPS=6
+
+step() {
+    CURRENT_STEP=$((CURRENT_STEP + 1))
+    printf '\n%s[%d/%d]%s %s%s%s\n' \
+        "${COLOR_BLUE}" "${CURRENT_STEP}" "${TOTAL_STEPS}" "${COLOR_RESET}" \
+        "${COLOR_BOLD}" "$1" "${COLOR_RESET}"
+}
+
+info()  { printf '%s  ->%s %s\n' "${COLOR_CYAN}" "${COLOR_RESET}" "$1"; }
+ok()    { printf '%s  ok%s %s\n' "${COLOR_GREEN}" "${COLOR_RESET}" "$1"; }
+warn()  { printf '%s  warn%s %s\n' "${COLOR_YELLOW}" "${COLOR_RESET}" "$1"; }
+error() { printf '%s  error%s %s\n' "${COLOR_RED}" "${COLOR_RESET}" "$1" 1>&2; }
+
+print_banner() {
+    printf '%s' "${COLOR_BOLD}"
+    cat <<'EOF'
+   ____  _                   ____          _
+  / ___|| |  __ _ __      __ / ___|___   __| | ___
+ | |    | | / _` |\ \ /\ / /| |   / _ \ / _` |/ _ \
+ | |___ | || (_| | \ V  V / | |__| (_) | (_| |  __/
+  \____||_| \__,_|  \_/\_/   \____\___/ \__,_|\___|
+EOF
+    printf '%s\n' "${COLOR_RESET}"
+    printf '%sClaw Code installer%s\n' "${COLOR_DIM}" "${COLOR_RESET}"
+}
+
+print_usage() {
+    cat <<'EOF'
+Usage: ./install.sh [options]
+
+Options:
+  --release       Build the optimized release profile (slower, smaller binary).
+  --debug         Build the debug profile (default, faster compile).
+  --no-verify     Skip the post-install verification step.
+  -h, --help      Show this help text and exit.
+
+Environment overrides:
+  CLAW_BUILD_PROFILE   debug | release
+  CLAW_SKIP_VERIFY     set to 1 to skip verification
+EOF
+}
+
+# ---------------------------------------------------------------------------
+# Argument parsing
+# ---------------------------------------------------------------------------
+
+BUILD_PROFILE="${CLAW_BUILD_PROFILE:-debug}"
+SKIP_VERIFY="${CLAW_SKIP_VERIFY:-0}"
+
+while [ "$#" -gt 0 ]; do
+    case "$1" in
+        --release)
+            BUILD_PROFILE="release"
+            ;;
+        --debug)
+            BUILD_PROFILE="debug"
+            ;;
+        --no-verify)
+            SKIP_VERIFY="1"
+            ;;
+        -h|--help)
+            print_usage
+            exit 0
+            ;;
+        *)
+            error "unknown argument: $1"
+            print_usage
+            exit 2
+            ;;
+    esac
+    shift
+done
+
+case "${BUILD_PROFILE}" in
+    debug|release) ;;
+    *)
+        error "invalid build profile: ${BUILD_PROFILE} (expected debug or release)"
+        exit 2
+        ;;
+esac
+
+# ---------------------------------------------------------------------------
+# Troubleshooting hints
+# ---------------------------------------------------------------------------
+
+print_troubleshooting() {
+    cat <<EOF
+
+${COLOR_BOLD}Troubleshooting${COLOR_RESET}
+${COLOR_DIM}---------------${COLOR_RESET}
+
+  ${COLOR_BOLD}1. Rust toolchain missing${COLOR_RESET}
+     Install Rust via rustup:
+       curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
+     Then reload your shell or run:
+       source "\$HOME/.cargo/env"
+
+  ${COLOR_BOLD}2. Linux: missing system packages${COLOR_RESET}
+     The build needs git, pkg-config, and OpenSSL headers.
+     Debian/Ubuntu:
+       sudo apt-get update && sudo apt-get install -y \\
+         git pkg-config libssl-dev ca-certificates build-essential
+     Fedora/RHEL:
+       sudo dnf install -y git pkgconf-pkg-config openssl-devel gcc
+     Arch:
+       sudo pacman -S --needed git pkgconf openssl base-devel
+
+  ${COLOR_BOLD}3. macOS: missing Xcode CLT${COLOR_RESET}
+     Install the command line tools:
+       xcode-select --install
+
+  ${COLOR_BOLD}4. Windows users${COLOR_RESET}
+     Run this script from inside a WSL distro (Ubuntu/Debian recommended).
+     Native Windows builds are not supported by this installer.
+
+  ${COLOR_BOLD}5. Build fails partway through${COLOR_RESET}
+     Try a clean build:
+       cd rust && cargo clean && cargo build --workspace
+     If the failure mentions ring/openssl, double check step 2.
+
+  ${COLOR_BOLD}6. 'claw' not found after install${COLOR_RESET}
+     The binary lives at:
+       rust/target/${BUILD_PROFILE}/claw
+     Add it to your PATH or invoke it with the full path.
+
+EOF
+}
+
+trap 'rc=$?; if [ "$rc" -ne 0 ]; then error "installation failed (exit ${rc})"; print_troubleshooting; fi' EXIT
+
+# ---------------------------------------------------------------------------
+# Helpers
+# ---------------------------------------------------------------------------
+
+require_cmd() {
+    command -v "$1" >/dev/null 2>&1
+}
+
+# ---------------------------------------------------------------------------
+# Step 1: detect OS / arch / WSL
+# ---------------------------------------------------------------------------
+
+print_banner
+step "Detecting host environment"
+
+UNAME_S="$(uname -s 2>/dev/null || echo unknown)"
+UNAME_M="$(uname -m 2>/dev/null || echo unknown)"
+OS_FAMILY="unknown"
+IS_WSL="0"
+
+case "${UNAME_S}" in
+    Linux*)
+        OS_FAMILY="linux"
+        if grep -qiE 'microsoft|wsl' /proc/version 2>/dev/null; then
+            IS_WSL="1"
+        fi
+        ;;
+    Darwin*)
+        OS_FAMILY="macos"
+        ;;
+    MINGW*|MSYS*|CYGWIN*)
+        OS_FAMILY="windows-shell"
+        ;;
+esac
+
+info "uname:        ${UNAME_S} ${UNAME_M}"
+info "os family:    ${OS_FAMILY}"
+if [ "${IS_WSL}" = "1" ]; then
+    info "wsl:          yes"
+fi
+
+case "${OS_FAMILY}" in
+    linux|macos)
+        ok "supported platform detected"
+        ;;
+    windows-shell)
+        error "Detected a native Windows shell (MSYS/Cygwin/MinGW)."
+        error "Please re-run this script from inside a WSL distribution."
+        exit 1
+        ;;
+    *)
+        error "Unsupported or unknown OS: ${UNAME_S}"
+        error "Supported: Linux, macOS, and Windows via WSL."
+        exit 1
+        ;;
+esac
+
+# ---------------------------------------------------------------------------
+# Step 2: locate the Rust workspace
+# ---------------------------------------------------------------------------
+
+step "Locating the Rust workspace"
+
+SCRIPT_DIR="$(cd "$(dirname "$0")" && pwd)"
+RUST_DIR="${SCRIPT_DIR}/rust"
+
+if [ ! -d "${RUST_DIR}" ]; then
+    error "Could not find rust/ workspace next to install.sh"
+    error "Expected: ${RUST_DIR}"
+    exit 1
+fi
+
+if [ ! -f "${RUST_DIR}/Cargo.toml" ]; then
+    error "Missing ${RUST_DIR}/Cargo.toml — repository layout looks unexpected."
+    exit 1
+fi
+
+ok "workspace at ${RUST_DIR}"
+
+# ---------------------------------------------------------------------------
+# Step 3: prerequisite checks
+# ---------------------------------------------------------------------------
+
+step "Checking prerequisites"
+
+MISSING_PREREQS=0
+
+if require_cmd rustc; then
+    RUSTC_VERSION="$(rustc --version 2>/dev/null || echo 'unknown')"
+    ok "rustc found: ${RUSTC_VERSION}"
+else
+    error "rustc not found in PATH"
+    MISSING_PREREQS=1
+fi
+
+if require_cmd cargo; then
+    CARGO_VERSION="$(cargo --version 2>/dev/null || echo 'unknown')"
+    ok "cargo found: ${CARGO_VERSION}"
+else
+    error "cargo not found in PATH"
+    MISSING_PREREQS=1
+fi
+
+if require_cmd git; then
+    ok "git found:  $(git --version 2>/dev/null || echo 'unknown')"
+else
+    warn "git not found — some workflows (login, session export) may degrade"
+fi
+
+if [ "${OS_FAMILY}" = "linux" ]; then
+    if require_cmd pkg-config; then
+        ok "pkg-config found"
+    else
+        warn "pkg-config not found — may be required for OpenSSL-linked crates"
+    fi
+fi
+
+if [ "${OS_FAMILY}" = "macos" ]; then
+    if ! require_cmd cc && ! xcode-select -p >/dev/null 2>&1; then
+        warn "Xcode command line tools not detected — run: xcode-select --install"
+    fi
+fi
+
+if [ "${MISSING_PREREQS}" -ne 0 ]; then
+    error "Missing required tools. See troubleshooting below."
+    exit 1
+fi
+
+# ---------------------------------------------------------------------------
+# Step 4: build the workspace
+# ---------------------------------------------------------------------------
+
+step "Building the claw workspace (${BUILD_PROFILE})"
+
+CARGO_FLAGS=("build" "--workspace")
+if [ "${BUILD_PROFILE}" = "release" ]; then
+    CARGO_FLAGS+=("--release")
+fi
+
+info "running: cargo ${CARGO_FLAGS[*]}"
+info "this may take a few minutes on the first build"
+
+(
+    cd "${RUST_DIR}"
+    CARGO_TERM_COLOR="${CARGO_TERM_COLOR:-always}" cargo "${CARGO_FLAGS[@]}"
+)
+
+CLAW_BIN="${RUST_DIR}/target/${BUILD_PROFILE}/claw"
+
+if [ ! -x "${CLAW_BIN}" ]; then
+    error "Expected binary not found at ${CLAW_BIN}"
+    error "The build reported success but the binary is missing — check cargo output above."
+    exit 1
+fi
+
+ok "built ${CLAW_BIN}"
+
+# ---------------------------------------------------------------------------
+# Step 5: post-install verification
+# ---------------------------------------------------------------------------
+
+step "Verifying the installed binary"
+
+if [ "${SKIP_VERIFY}" = "1" ]; then
+    warn "verification skipped (--no-verify or CLAW_SKIP_VERIFY=1)"
+else
+    info "running: claw --version"
+    if VERSION_OUT="$("${CLAW_BIN}" --version 2>&1)"; then
+        ok "claw --version -> ${VERSION_OUT}"
+    else
+        error "claw --version failed:"
+        printf '%s\n' "${VERSION_OUT}" 1>&2
+        exit 1
+    fi
+
+    info "running: claw --help (smoke test)"
+    if "${CLAW_BIN}" --help >/dev/null 2>&1; then
+        ok "claw --help responded"
+    else
+        error "claw --help failed"
+        exit 1
+    fi
+fi
+
+# ---------------------------------------------------------------------------
+# Step 6: next steps
+# ---------------------------------------------------------------------------
+
+step "Next steps"
+
+cat <<EOF
+${COLOR_GREEN}Claw Code is built and ready.${COLOR_RESET}
+
+  Binary:  ${COLOR_BOLD}${CLAW_BIN}${COLOR_RESET}
+  Profile: ${BUILD_PROFILE}
+
+Try it out:
+
+  ${COLOR_DIM}# interactive REPL${COLOR_RESET}
+  ${CLAW_BIN}
+
+  ${COLOR_DIM}# one-shot prompt${COLOR_RESET}
+  ${CLAW_BIN} prompt "summarize this repository"
+
+  ${COLOR_DIM}# health check (run /doctor inside the REPL)${COLOR_RESET}
+  ${CLAW_BIN}
+  /doctor
+
+Authentication:
+
+  export ANTHROPIC_API_KEY="sk-ant-..."
+  ${COLOR_DIM}# or use OAuth:${COLOR_RESET}
+  ${CLAW_BIN} login
+
+For deeper docs, see USAGE.md and rust/README.md.
+EOF
+
+# clear the failure trap on clean exit
+trap - EXIT

rust/Cargo.lock

@@ -1580,6 +1580,7 @@ version = "0.1.0"
 dependencies = [
  "api",
  "commands",
+ "flate2",
  "plugins",
  "reqwest",
  "runtime",

rust/crates/api/src/error.rs

@@ -35,7 +35,12 @@ pub enum ApiError {
     InvalidApiKeyEnv(VarError),
     Http(reqwest::Error),
     Io(std::io::Error),
-    Json(serde_json::Error),
+    Json {
+        provider: String,
+        model: String,
+        body_snippet: String,
+        source: serde_json::Error,
+    },
     Api {
         status: reqwest::StatusCode,
         error_type: Option<String>,
@@ -64,6 +69,25 @@ impl ApiError {
         Self::MissingCredentials { provider, env_vars }
     }
 
+    /// Build a `Self::Json` enriched with the provider name, the model that
+    /// was requested, and the first 200 characters of the raw response body so
+    /// that callers can diagnose deserialization failures without re-running
+    /// the request.
+    #[must_use]
+    pub fn json_deserialize(
+        provider: impl Into<String>,
+        model: impl Into<String>,
+        body: &str,
+        source: serde_json::Error,
+    ) -> Self {
+        Self::Json {
+            provider: provider.into(),
+            model: model.into(),
+            body_snippet: truncate_body_snippet(body, 200),
+            source,
+        }
+    }
+
     #[must_use]
     pub fn is_retryable(&self) -> bool {
         match self {
@@ -76,7 +100,7 @@ impl ApiError {
             | Self::Auth(_)
             | Self::InvalidApiKeyEnv(_)
             | Self::Io(_)
-            | Self::Json(_)
+            | Self::Json { .. }
             | Self::InvalidSseFrame(_)
             | Self::BackoffOverflow { .. } => false,
         }
@@ -94,7 +118,7 @@ impl ApiError {
             | Self::InvalidApiKeyEnv(_)
             | Self::Http(_)
             | Self::Io(_)
-            | Self::Json(_)
+            | Self::Json { .. }
             | Self::InvalidSseFrame(_)
             | Self::BackoffOverflow { .. } => None,
         }
@@ -120,7 +144,7 @@ impl ApiError {
             Self::Http(_) | Self::InvalidSseFrame(_) | Self::BackoffOverflow { .. } => {
                 "provider_transport"
             }
-            Self::InvalidApiKeyEnv(_) | Self::Io(_) | Self::Json(_) => "runtime_io",
+            Self::InvalidApiKeyEnv(_) | Self::Io(_) | Self::Json { .. } => "runtime_io",
         }
     }
 
@@ -141,7 +165,7 @@ impl ApiError {
             | Self::InvalidApiKeyEnv(_)
             | Self::Http(_)
             | Self::Io(_)
-            | Self::Json(_)
+            | Self::Json { .. }
             | Self::InvalidSseFrame(_)
             | Self::BackoffOverflow { .. } => false,
         }
@@ -170,7 +194,7 @@ impl ApiError {
             | Self::InvalidApiKeyEnv(_)
             | Self::Http(_)
             | Self::Io(_)
-            | Self::Json(_)
+            | Self::Json { .. }
             | Self::InvalidSseFrame(_)
             | Self::BackoffOverflow { .. } => false,
         }
@@ -180,11 +204,27 @@ impl ApiError {
 impl Display for ApiError {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         match self {
-            Self::MissingCredentials { provider, env_vars } => write!(
-                f,
-                "missing {provider} credentials; export {} before calling the {provider} API",
-                env_vars.join(" or ")
-            ),
+            Self::MissingCredentials { provider, env_vars } => {
+                write!(
+                    f,
+                    "missing {provider} credentials; export {} before calling the {provider} API",
+                    env_vars.join(" or ")
+                )?;
+                if cfg!(target_os = "windows") {
+                    if let Some(primary) = env_vars.first() {
+                        write!(
+                            f,
+                            " (on Windows, environment variables set in PowerShell only persist for the current session; use `setx {primary} <value>` to make it permanent, then open a new terminal, or place a `.env` file containing `{primary}=<value>` in the current working directory)"
+                        )?;
+                    } else {
+                        write!(
+                            f,
+                            " (on Windows, environment variables set in PowerShell only persist for the current session; use `setx` to make them permanent, then open a new terminal, or place a `.env` file in the current working directory)"
+                        )?;
+                    }
+                }
+                Ok(())
+            }
             Self::ContextWindowExceeded {
                 model,
                 estimated_input_tokens,
@@ -207,7 +247,15 @@ impl Display for ApiError {
             }
             Self::Http(error) => write!(f, "http error: {error}"),
             Self::Io(error) => write!(f, "io error: {error}"),
-            Self::Json(error) => write!(f, "json error: {error}"),
+            Self::Json {
+                provider,
+                model,
+                body_snippet,
+                source,
+            } => write!(
+                f,
+                "failed to parse {provider} response for model {model}: {source}; first 200 chars of body: {body_snippet}"
+            ),
             Self::Api {
                 status,
                 error_type,
@@ -262,7 +310,12 @@ impl From<std::io::Error> for ApiError {
 
 impl From<serde_json::Error> for ApiError {
     fn from(value: serde_json::Error) -> Self {
-        Self::Json(value)
+        Self::Json {
+            provider: "unknown".to_string(),
+            model: "unknown".to_string(),
+            body_snippet: String::new(),
+            source: value,
+        }
     }
 }
 
@@ -286,9 +339,89 @@ fn looks_like_context_window_error(text: &str) -> bool {
         .any(|marker| lowered.contains(marker))
 }
 
+/// Truncate `body` so the resulting snippet contains at most `max_chars`
+/// characters (counted by Unicode scalar values, not bytes), preserving the
+/// leading slice of the body that the caller most often needs to inspect.
+fn truncate_body_snippet(body: &str, max_chars: usize) -> String {
+    let mut taken_chars = 0;
+    let mut byte_end = 0;
+    for (offset, character) in body.char_indices() {
+        if taken_chars >= max_chars {
+            break;
+        }
+        taken_chars += 1;
+        byte_end = offset + character.len_utf8();
+    }
+    if taken_chars >= max_chars && byte_end < body.len() {
+        format!("{}…", &body[..byte_end])
+    } else {
+        body[..byte_end].to_string()
+    }
+}
+
 #[cfg(test)]
 mod tests {
-    use super::ApiError;
+    use super::{truncate_body_snippet, ApiError};
+
+    #[test]
+    fn json_deserialize_error_includes_provider_model_and_truncated_body_snippet() {
+        let raw_body = format!("{}{}", "x".repeat(190), "_TAIL_PAST_200_CHARS_MARKER_");
+        let source = serde_json::from_str::<serde_json::Value>("{not json")
+            .expect_err("invalid json should fail to parse");
+
+        let error = ApiError::json_deserialize("Anthropic", "claude-opus-4-6", &raw_body, source);
+        let rendered = error.to_string();
+
+        assert!(
+            rendered.starts_with("failed to parse Anthropic response for model claude-opus-4-6: "),
+            "rendered error should lead with provider and model: {rendered}"
+        );
+        assert!(
+            rendered.contains("first 200 chars of body: "),
+            "rendered error should label the body snippet: {rendered}"
+        );
+        let snippet = rendered
+            .split("first 200 chars of body: ")
+            .nth(1)
+            .expect("snippet section should be present");
+        assert!(
+            snippet.starts_with(&"x".repeat(190)),
+            "snippet should preserve the leading characters of the body: {snippet}"
+        );
+        assert!(
+            snippet.ends_with('…'),
+            "snippet should signal truncation with an ellipsis: {snippet}"
+        );
+        assert!(
+            !snippet.contains("_TAIL_PAST_200_CHARS_MARKER_"),
+            "snippet should drop characters past the 200-char cap: {snippet}"
+        );
+        assert_eq!(error.safe_failure_class(), "runtime_io");
+        assert_eq!(error.request_id(), None);
+        assert!(!error.is_retryable());
+    }
+
+    #[test]
+    fn truncate_body_snippet_keeps_short_bodies_intact() {
+        assert_eq!(truncate_body_snippet("hello", 200), "hello");
+        assert_eq!(truncate_body_snippet("", 200), "");
+    }
+
+    #[test]
+    fn truncate_body_snippet_caps_long_bodies_at_max_chars() {
+        let body = "a".repeat(250);
+        let snippet = truncate_body_snippet(&body, 200);
+        assert_eq!(snippet.chars().count(), 201, "200 chars + ellipsis");
+        assert!(snippet.ends_with('…'));
+        assert!(snippet.starts_with(&"a".repeat(200)));
+    }
+
+    #[test]
+    fn truncate_body_snippet_does_not_split_multibyte_characters() {
+        let body = "한글한글한글한글한글한글";
+        let snippet = truncate_body_snippet(body, 4);
+        assert_eq!(snippet, "한글한글…");
+    }
 
     #[test]
     fn detects_generic_fatal_wrapper_and_classifies_it_as_provider_internal() {

rust/crates/api/src/http_client.rs

@@ -0,0 +1,344 @@
+use crate::error::ApiError;
+
+const HTTP_PROXY_KEYS: [&str; 2] = ["HTTP_PROXY", "http_proxy"];
+const HTTPS_PROXY_KEYS: [&str; 2] = ["HTTPS_PROXY", "https_proxy"];
+const NO_PROXY_KEYS: [&str; 2] = ["NO_PROXY", "no_proxy"];
+
+/// Snapshot of the proxy-related environment variables that influence the
+/// outbound HTTP client. Captured up front so callers can inspect, log, and
+/// test the resolved configuration without re-reading the process environment.
+///
+/// When `proxy_url` is set it acts as a single catch-all proxy for both
+/// HTTP and HTTPS traffic, taking precedence over the per-scheme fields.
+#[derive(Debug, Clone, Default, PartialEq, Eq)]
+pub struct ProxyConfig {
+    pub http_proxy: Option<String>,
+    pub https_proxy: Option<String>,
+    pub no_proxy: Option<String>,
+    /// Optional unified proxy URL that applies to both HTTP and HTTPS.
+    /// When set, this takes precedence over `http_proxy` and `https_proxy`.
+    pub proxy_url: Option<String>,
+}
+
+impl ProxyConfig {
+    /// Read proxy settings from the live process environment, honouring both
+    /// the upper- and lower-case spellings used by curl, git, and friends.
+    #[must_use]
+    pub fn from_env() -> Self {
+        Self::from_lookup(|key| std::env::var(key).ok())
+    }
+
+    /// Create a proxy configuration from a single URL that applies to both
+    /// HTTP and HTTPS traffic. This is the config-file alternative to setting
+    /// `HTTP_PROXY` and `HTTPS_PROXY` environment variables separately.
+    #[must_use]
+    pub fn from_proxy_url(url: impl Into<String>) -> Self {
+        Self {
+            proxy_url: Some(url.into()),
+            ..Self::default()
+        }
+    }
+
+    fn from_lookup<F>(mut lookup: F) -> Self
+    where
+        F: FnMut(&str) -> Option<String>,
+    {
+        Self {
+            http_proxy: first_non_empty(&HTTP_PROXY_KEYS, &mut lookup),
+            https_proxy: first_non_empty(&HTTPS_PROXY_KEYS, &mut lookup),
+            no_proxy: first_non_empty(&NO_PROXY_KEYS, &mut lookup),
+            proxy_url: None,
+        }
+    }
+
+    #[must_use]
+    pub fn is_empty(&self) -> bool {
+        self.proxy_url.is_none() && self.http_proxy.is_none() && self.https_proxy.is_none()
+    }
+}
+
+/// Build a `reqwest::Client` that honours the standard `HTTP_PROXY`,
+/// `HTTPS_PROXY`, and `NO_PROXY` environment variables. When no proxy is
+/// configured the client behaves identically to `reqwest::Client::new()`.
+pub fn build_http_client() -> Result<reqwest::Client, ApiError> {
+    build_http_client_with(&ProxyConfig::from_env())
+}
+
+/// Infallible counterpart to [`build_http_client`] for constructors that
+/// historically returned `Self` rather than `Result<Self, _>`. When the proxy
+/// configuration is malformed we fall back to a default client so that
+/// callers retain the previous behaviour and the failure surfaces on the
+/// first outbound request instead of at construction time.
+#[must_use]
+pub fn build_http_client_or_default() -> reqwest::Client {
+    build_http_client().unwrap_or_else(|_| reqwest::Client::new())
+}
+
+/// Build a `reqwest::Client` from an explicit [`ProxyConfig`]. Used by tests
+/// and by callers that want to override process-level environment lookups.
+///
+/// When `config.proxy_url` is set it overrides the per-scheme `http_proxy`
+/// and `https_proxy` fields and is registered as both an HTTP and HTTPS
+/// proxy so a single value can route every outbound request.
+pub fn build_http_client_with(config: &ProxyConfig) -> Result<reqwest::Client, ApiError> {
+    let mut builder = reqwest::Client::builder().no_proxy();
+
+    let no_proxy = config
+        .no_proxy
+        .as_deref()
+        .and_then(reqwest::NoProxy::from_string);
+
+    let (http_proxy_url, https_proxy_url) = match config.proxy_url.as_deref() {
+        Some(unified) => (Some(unified), Some(unified)),
+        None => (config.http_proxy.as_deref(), config.https_proxy.as_deref()),
+    };
+
+    if let Some(url) = https_proxy_url {
+        let mut proxy = reqwest::Proxy::https(url)?;
+        if let Some(filter) = no_proxy.clone() {
+            proxy = proxy.no_proxy(Some(filter));
+        }
+        builder = builder.proxy(proxy);
+    }
+
+    if let Some(url) = http_proxy_url {
+        let mut proxy = reqwest::Proxy::http(url)?;
+        if let Some(filter) = no_proxy.clone() {
+            proxy = proxy.no_proxy(Some(filter));
+        }
+        builder = builder.proxy(proxy);
+    }
+
+    Ok(builder.build()?)
+}
+
+fn first_non_empty<F>(keys: &[&str], lookup: &mut F) -> Option<String>
+where
+    F: FnMut(&str) -> Option<String>,
+{
+    keys.iter()
+        .find_map(|key| lookup(key).filter(|value| !value.is_empty()))
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::HashMap;
+
+    use super::{build_http_client_with, ProxyConfig};
+
+    fn config_from_map(pairs: &[(&str, &str)]) -> ProxyConfig {
+        let map: HashMap<String, String> = pairs
+            .iter()
+            .map(|(key, value)| ((*key).to_string(), (*value).to_string()))
+            .collect();
+        ProxyConfig::from_lookup(|key| map.get(key).cloned())
+    }
+
+    #[test]
+    fn proxy_config_is_empty_when_no_env_vars_are_set() {
+        // given
+        let config = config_from_map(&[]);
+
+        // when
+        let empty = config.is_empty();
+
+        // then
+        assert!(empty);
+        assert_eq!(config, ProxyConfig::default());
+    }
+
+    #[test]
+    fn proxy_config_reads_uppercase_http_https_and_no_proxy() {
+        // given
+        let pairs = [
+            ("HTTP_PROXY", "http://proxy.internal:3128"),
+            ("HTTPS_PROXY", "http://secure.internal:3129"),
+            ("NO_PROXY", "localhost,127.0.0.1,.corp"),
+        ];
+
+        // when
+        let config = config_from_map(&pairs);
+
+        // then
+        assert_eq!(
+            config.http_proxy.as_deref(),
+            Some("http://proxy.internal:3128")
+        );
+        assert_eq!(
+            config.https_proxy.as_deref(),
+            Some("http://secure.internal:3129")
+        );
+        assert_eq!(
+            config.no_proxy.as_deref(),
+            Some("localhost,127.0.0.1,.corp")
+        );
+        assert!(!config.is_empty());
+    }
+
+    #[test]
+    fn proxy_config_falls_back_to_lowercase_keys() {
+        // given
+        let pairs = [
+            ("http_proxy", "http://lower.internal:3128"),
+            ("https_proxy", "http://lower-secure.internal:3129"),
+            ("no_proxy", ".lower"),
+        ];
+
+        // when
+        let config = config_from_map(&pairs);
+
+        // then
+        assert_eq!(
+            config.http_proxy.as_deref(),
+            Some("http://lower.internal:3128")
+        );
+        assert_eq!(
+            config.https_proxy.as_deref(),
+            Some("http://lower-secure.internal:3129")
+        );
+        assert_eq!(config.no_proxy.as_deref(), Some(".lower"));
+    }
+
+    #[test]
+    fn proxy_config_prefers_uppercase_over_lowercase_when_both_set() {
+        // given
+        let pairs = [
+            ("HTTP_PROXY", "http://upper.internal:3128"),
+            ("http_proxy", "http://lower.internal:3128"),
+        ];
+
+        // when
+        let config = config_from_map(&pairs);
+
+        // then
+        assert_eq!(
+            config.http_proxy.as_deref(),
+            Some("http://upper.internal:3128")
+        );
+    }
+
+    #[test]
+    fn proxy_config_treats_empty_strings_as_unset() {
+        // given
+        let pairs = [("HTTP_PROXY", ""), ("http_proxy", "")];
+
+        // when
+        let config = config_from_map(&pairs);
+
+        // then
+        assert!(config.http_proxy.is_none());
+    }
+
+    #[test]
+    fn build_http_client_succeeds_when_no_proxy_is_configured() {
+        // given
+        let config = ProxyConfig::default();
+
+        // when
+        let result = build_http_client_with(&config);
+
+        // then
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn build_http_client_succeeds_with_valid_http_and_https_proxies() {
+        // given
+        let config = ProxyConfig {
+            http_proxy: Some("http://proxy.internal:3128".to_string()),
+            https_proxy: Some("http://secure.internal:3129".to_string()),
+            no_proxy: Some("localhost,127.0.0.1".to_string()),
+            proxy_url: None,
+        };
+
+        // when
+        let result = build_http_client_with(&config);
+
+        // then
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn build_http_client_returns_http_error_for_invalid_proxy_url() {
+        // given
+        let config = ProxyConfig {
+            http_proxy: None,
+            https_proxy: Some("not a url".to_string()),
+            no_proxy: None,
+            proxy_url: None,
+        };
+
+        // when
+        let result = build_http_client_with(&config);
+
+        // then
+        let error = result.expect_err("invalid proxy URL must be reported as a build failure");
+        assert!(
+            matches!(error, crate::error::ApiError::Http(_)),
+            "expected ApiError::Http for invalid proxy URL, got: {error:?}"
+        );
+    }
+
+    #[test]
+    fn from_proxy_url_sets_unified_field_and_leaves_per_scheme_empty() {
+        // given / when
+        let config = ProxyConfig::from_proxy_url("http://unified.internal:3128");
+
+        // then
+        assert_eq!(
+            config.proxy_url.as_deref(),
+            Some("http://unified.internal:3128")
+        );
+        assert!(config.http_proxy.is_none());
+        assert!(config.https_proxy.is_none());
+        assert!(!config.is_empty());
+    }
+
+    #[test]
+    fn build_http_client_succeeds_with_unified_proxy_url() {
+        // given
+        let config = ProxyConfig {
+            proxy_url: Some("http://unified.internal:3128".to_string()),
+            no_proxy: Some("localhost".to_string()),
+            ..ProxyConfig::default()
+        };
+
+        // when
+        let result = build_http_client_with(&config);
+
+        // then
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn proxy_url_takes_precedence_over_per_scheme_fields() {
+        // given – both per-scheme and unified are set
+        let config = ProxyConfig {
+            http_proxy: Some("http://per-scheme.internal:1111".to_string()),
+            https_proxy: Some("http://per-scheme.internal:2222".to_string()),
+            no_proxy: None,
+            proxy_url: Some("http://unified.internal:3128".to_string()),
+        };
+
+        // when – building succeeds (the unified URL is valid)
+        let result = build_http_client_with(&config);
+
+        // then
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn build_http_client_returns_error_for_invalid_unified_proxy_url() {
+        // given
+        let config = ProxyConfig::from_proxy_url("not a url");
+
+        // when
+        let result = build_http_client_with(&config);
+
+        // then
+        assert!(
+            matches!(result, Err(crate::error::ApiError::Http(_))),
+            "invalid unified proxy URL should fail: {result:?}"
+        );
+    }
+}

rust/crates/api/src/lib.rs

@@ -1,5 +1,6 @@
 mod client;
 mod error;
+mod http_client;
 mod prompt_cache;
 mod providers;
 mod sse;
@@ -10,6 +11,9 @@ pub use client::{
     resolve_startup_auth_source, MessageStream, OAuthTokenSet, ProviderClient,
 };
 pub use error::ApiError;
+pub use http_client::{
+    build_http_client, build_http_client_or_default, build_http_client_with, ProxyConfig,
+};
 pub use prompt_cache::{
     CacheBreakEvent, PromptCache, PromptCacheConfig, PromptCachePaths, PromptCacheRecord,
     PromptCacheStats,
@@ -17,7 +21,8 @@ pub use prompt_cache::{
 pub use providers::anthropic::{AnthropicClient, AnthropicClient as ApiClient, AuthSource};
 pub use providers::openai_compat::{OpenAiCompatClient, OpenAiCompatConfig};
 pub use providers::{
-    detect_provider_kind, max_tokens_for_model, resolve_model_alias, ProviderKind,
+    detect_provider_kind, max_tokens_for_model, max_tokens_for_model_with_override,
+    resolve_model_alias, ProviderKind,
 };
 pub use sse::{parse_frame, SseParser};
 pub use types::{

rust/crates/api/src/providers/anthropic.rs

@@ -1,4 +1,5 @@
 use std::collections::VecDeque;
+use std::sync::atomic::{AtomicU64, Ordering};
 use std::sync::{Arc, Mutex};
 use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
@@ -12,6 +13,7 @@ use serde_json::{Map, Value};
 use telemetry::{AnalyticsEvent, AnthropicRequestProfile, ClientIdentity, SessionTracer};
 
 use crate::error::ApiError;
+use crate::http_client::build_http_client_or_default;
 use crate::prompt_cache::{PromptCache, PromptCacheRecord, PromptCacheStats};
 
 use super::{model_token_limit, resolve_model_alias, Provider, ProviderFuture};
@@ -21,9 +23,9 @@ use crate::types::{MessageDeltaEvent, MessageRequest, MessageResponse, StreamEve
 pub const DEFAULT_BASE_URL: &str = "https://api.anthropic.com";
 const REQUEST_ID_HEADER: &str = "request-id";
 const ALT_REQUEST_ID_HEADER: &str = "x-request-id";
-const DEFAULT_INITIAL_BACKOFF: Duration = Duration::from_millis(200);
-const DEFAULT_MAX_BACKOFF: Duration = Duration::from_secs(2);
-const DEFAULT_MAX_RETRIES: u32 = 2;
+const DEFAULT_INITIAL_BACKOFF: Duration = Duration::from_secs(1);
+const DEFAULT_MAX_BACKOFF: Duration = Duration::from_secs(128);
+const DEFAULT_MAX_RETRIES: u32 = 8;
 
 #[derive(Debug, Clone, PartialEq, Eq)]
 pub enum AuthSource {
@@ -127,7 +129,7 @@ impl AnthropicClient {
     #[must_use]
     pub fn new(api_key: impl Into<String>) -> Self {
         Self {
-            http: reqwest::Client::new(),
+            http: build_http_client_or_default(),
             auth: AuthSource::ApiKey(api_key.into()),
             base_url: DEFAULT_BASE_URL.to_string(),
             max_retries: DEFAULT_MAX_RETRIES,
@@ -143,7 +145,7 @@ impl AnthropicClient {
     #[must_use]
     pub fn from_auth(auth: AuthSource) -> Self {
         Self {
-            http: reqwest::Client::new(),
+            http: build_http_client_or_default(),
             auth,
             base_url: DEFAULT_BASE_URL.to_string(),
             max_retries: DEFAULT_MAX_RETRIES,
@@ -296,12 +298,12 @@ impl AnthropicClient {
 
         self.preflight_message_request(&request).await?;
 
-        let response = self.send_with_retry(&request).await?;
-        let request_id = request_id_from_headers(response.headers());
-        let mut response = response
-            .json::<MessageResponse>()
-            .await
-            .map_err(ApiError::from)?;
+        let http_response = self.send_with_retry(&request).await?;
+        let request_id = request_id_from_headers(http_response.headers());
+        let body = http_response.text().await.map_err(ApiError::from)?;
+        let mut response = serde_json::from_str::<MessageResponse>(&body).map_err(|error| {
+            ApiError::json_deserialize("Anthropic", &request.model, &body, error)
+        })?;
         if response.request_id.is_none() {
             response.request_id = request_id;
         }
@@ -346,7 +348,7 @@ impl AnthropicClient {
         Ok(MessageStream {
             request_id: request_id_from_headers(response.headers()),
             response,
-            parser: SseParser::new(),
+            parser: SseParser::new().with_context("Anthropic", request.model.clone()),
             pending: VecDeque::new(),
             done: false,
             request: request.clone(),
@@ -371,10 +373,10 @@ impl AnthropicClient {
             .await
             .map_err(ApiError::from)?;
         let response = expect_success(response).await?;
-        response
-            .json::<OAuthTokenSet>()
-            .await
-            .map_err(ApiError::from)
+        let body = response.text().await.map_err(ApiError::from)?;
+        serde_json::from_str::<OAuthTokenSet>(&body).map_err(|error| {
+            ApiError::json_deserialize("Anthropic OAuth (exchange)", "n/a", &body, error)
+        })
     }
 
     pub async fn refresh_oauth_token(
@@ -391,10 +393,10 @@ impl AnthropicClient {
             .await
             .map_err(ApiError::from)?;
         let response = expect_success(response).await?;
-        response
-            .json::<OAuthTokenSet>()
-            .await
-            .map_err(ApiError::from)
+        let body = response.text().await.map_err(ApiError::from)?;
+        serde_json::from_str::<OAuthTokenSet>(&body).map_err(|error| {
+            ApiError::json_deserialize("Anthropic OAuth (refresh)", "n/a", &body, error)
+        })
     }
 
     async fn send_with_retry(
@@ -452,7 +454,7 @@ impl AnthropicClient {
                 break;
             }
 
-            tokio::time::sleep(self.backoff_for_attempt(attempts)?).await;
+            tokio::time::sleep(self.jittered_backoff_for_attempt(attempts)?).await;
         }
 
         Err(ApiError::RetriesExhausted {
@@ -466,7 +468,8 @@ impl AnthropicClient {
         request: &MessageRequest,
     ) -> Result<reqwest::Response, ApiError> {
         let request_url = format!("{}/v1/messages", self.base_url.trim_end_matches('/'));
-        let request_body = self.request_profile.render_json_body(request)?;
+        let mut request_body = self.request_profile.render_json_body(request)?;
+        strip_unsupported_beta_body_fields(&mut request_body);
         let request_builder = self.build_request(&request_url).json(&request_body);
         request_builder.send().await.map_err(ApiError::from)
     }
@@ -513,7 +516,8 @@ impl AnthropicClient {
         }
 
         let request_url = format!("{}/v1/messages/count_tokens", self.base_url.trim_end_matches('/'));
-        let request_body = self.request_profile.render_json_body(request)?;
+        let mut request_body = self.request_profile.render_json_body(request)?;
+        strip_unsupported_beta_body_fields(&mut request_body);
         let response = self
             .build_request(&request_url)
             .json(&request_body)
@@ -521,11 +525,16 @@ impl AnthropicClient {
             .await
             .map_err(ApiError::from)?;
 
-        let parsed = expect_success(response)
-            .await?
-            .json::<CountTokensResponse>()
-            .await
-            .map_err(ApiError::from)?;
+        let response = expect_success(response).await?;
+        let body = response.text().await.map_err(ApiError::from)?;
+        let parsed = serde_json::from_str::<CountTokensResponse>(&body).map_err(|error| {
+            ApiError::json_deserialize(
+                "Anthropic count_tokens",
+                &request.model,
+                &body,
+                error,
+            )
+        })?;
         Ok(parsed.input_tokens)
     }
 
@@ -561,6 +570,40 @@ impl AnthropicClient {
             .checked_mul(multiplier)
             .map_or(self.max_backoff, |delay| delay.min(self.max_backoff)))
     }
+
+    fn jittered_backoff_for_attempt(&self, attempt: u32) -> Result<Duration, ApiError> {
+        let base = self.backoff_for_attempt(attempt)?;
+        Ok(base + jitter_for_base(base))
+    }
+}
+
+/// Process-wide counter that guarantees distinct jitter samples even when
+/// the system clock resolution is coarser than consecutive retry sleeps.
+static JITTER_COUNTER: AtomicU64 = AtomicU64::new(0);
+
+/// Returns a random additive jitter in `[0, base]` to decorrelate retries
+/// from multiple concurrent clients. Entropy is drawn from the nanosecond
+/// wall clock mixed with a monotonic counter and run through a splitmix64
+/// finalizer; adequate for retry jitter (no cryptographic requirement).
+fn jitter_for_base(base: Duration) -> Duration {
+    let base_nanos = u64::try_from(base.as_nanos()).unwrap_or(u64::MAX);
+    if base_nanos == 0 {
+        return Duration::ZERO;
+    }
+    let raw_nanos = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|elapsed| u64::try_from(elapsed.as_nanos()).unwrap_or(u64::MAX))
+        .unwrap_or(0);
+    let tick = JITTER_COUNTER.fetch_add(1, Ordering::Relaxed);
+    // splitmix64 finalizer — mixes the low bits so large bases still see
+    // jitter across their full range instead of being clamped to subsec nanos.
+    let mut mixed = raw_nanos.wrapping_add(tick).wrapping_add(0x9E37_79B9_7F4A_7C15);
+    mixed = (mixed ^ (mixed >> 30)).wrapping_mul(0xBF58_476D_1CE4_E5B9);
+    mixed = (mixed ^ (mixed >> 27)).wrapping_mul(0x94D0_49BB_1331_11EB);
+    mixed ^= mixed >> 31;
+    // Inclusive upper bound: jitter may equal `base`, matching "up to base".
+    let jitter_nanos = mixed % base_nanos.saturating_add(1);
+    Duration::from_nanos(jitter_nanos)
 }
 
 impl AuthSource {
@@ -725,7 +768,7 @@ fn now_unix_timestamp() -> u64 {
 fn read_env_non_empty(key: &str) -> Result<Option<String>, ApiError> {
     match std::env::var(key) {
         Ok(value) if !value.is_empty() => Ok(Some(value)),
-        Ok(_) | Err(std::env::VarError::NotPresent) => Ok(None),
+        Ok(_) | Err(std::env::VarError::NotPresent) => Ok(super::dotenv_value(key)),
         Err(error) => Err(ApiError::from(error)),
     }
 }
@@ -880,6 +923,16 @@ const fn is_retryable_status(status: reqwest::StatusCode) -> bool {
     matches!(status.as_u16(), 408 | 409 | 429 | 500 | 502 | 503 | 504)
 }
 
+/// Remove beta-only body fields that the standard `/v1/messages` and
+/// `/v1/messages/count_tokens` endpoints reject as `Extra inputs are not
+/// permitted`. The `betas` opt-in is communicated via the `anthropic-beta`
+/// HTTP header on these endpoints, never as a JSON body field.
+fn strip_unsupported_beta_body_fields(body: &mut Value) {
+    if let Some(object) = body.as_object_mut() {
+        object.remove("betas");
+    }
+}
+
 #[derive(Debug, Deserialize)]
 struct AnthropicErrorEnvelope {
     error: AnthropicErrorBody,
@@ -1232,6 +1285,58 @@ mod tests {
         );
     }
 
+    #[test]
+    fn jittered_backoff_stays_within_additive_bounds_and_varies() {
+        let client = AnthropicClient::new("test-key").with_retry_policy(
+            8,
+            Duration::from_secs(1),
+            Duration::from_secs(128),
+        );
+        let mut samples = Vec::with_capacity(64);
+        for _ in 0..64 {
+            let base = client.backoff_for_attempt(3).expect("base attempt 3");
+            let jittered = client
+                .jittered_backoff_for_attempt(3)
+                .expect("jittered attempt 3");
+            assert!(
+                jittered >= base,
+                "jittered delay {jittered:?} must be at least the base {base:?}"
+            );
+            assert!(
+                jittered <= base * 2,
+                "jittered delay {jittered:?} must not exceed base*2 {:?}",
+                base * 2
+            );
+            samples.push(jittered);
+        }
+        let distinct: std::collections::HashSet<_> = samples.iter().collect();
+        assert!(
+            distinct.len() > 1,
+            "jitter should produce varied delays across samples, got {samples:?}"
+        );
+    }
+
+    #[test]
+    fn default_retry_policy_matches_exponential_schedule() {
+        let client = AnthropicClient::new("test-key");
+        assert_eq!(
+            client.backoff_for_attempt(1).expect("attempt 1"),
+            Duration::from_secs(1)
+        );
+        assert_eq!(
+            client.backoff_for_attempt(2).expect("attempt 2"),
+            Duration::from_secs(2)
+        );
+        assert_eq!(
+            client.backoff_for_attempt(3).expect("attempt 3"),
+            Duration::from_secs(4)
+        );
+        assert_eq!(
+            client.backoff_for_attempt(8).expect("attempt 8"),
+            Duration::from_secs(128)
+        );
+    }
+
     #[test]
     fn retryable_statuses_are_detected() {
         assert!(super::is_retryable_status(
@@ -1296,4 +1401,73 @@ mod tests {
             Some("Bearer proxy-token")
         );
     }
+
+    #[test]
+    fn strip_unsupported_beta_body_fields_removes_betas_array() {
+        let mut body = serde_json::json!({
+            "model": "claude-sonnet-4-6",
+            "max_tokens": 1024,
+            "betas": ["claude-code-20250219", "prompt-caching-scope-2026-01-05"],
+            "metadata": {"source": "test"},
+        });
+
+        super::strip_unsupported_beta_body_fields(&mut body);
+
+        assert!(
+            body.get("betas").is_none(),
+            "betas body field must be stripped before sending to /v1/messages"
+        );
+        assert_eq!(
+            body.get("model").and_then(serde_json::Value::as_str),
+            Some("claude-sonnet-4-6")
+        );
+        assert_eq!(body["max_tokens"], serde_json::json!(1024));
+        assert_eq!(body["metadata"]["source"], serde_json::json!("test"));
+    }
+
+    #[test]
+    fn strip_unsupported_beta_body_fields_is_a_noop_when_betas_absent() {
+        let mut body = serde_json::json!({
+            "model": "claude-sonnet-4-6",
+            "max_tokens": 1024,
+        });
+        let original = body.clone();
+
+        super::strip_unsupported_beta_body_fields(&mut body);
+
+        assert_eq!(body, original);
+    }
+
+    #[test]
+    fn rendered_request_body_strips_betas_for_standard_messages_endpoint() {
+        let client = AnthropicClient::new("test-key").with_beta("tools-2026-04-01");
+        let request = MessageRequest {
+            model: "claude-sonnet-4-6".to_string(),
+            max_tokens: 64,
+            messages: vec![],
+            system: None,
+            tools: None,
+            tool_choice: None,
+            stream: false,
+        };
+
+        let mut rendered = client
+            .request_profile()
+            .render_json_body(&request)
+            .expect("body should render");
+        assert!(
+            rendered.get("betas").is_some(),
+            "render_json_body still emits betas; the strip helper guards the wire format",
+        );
+        super::strip_unsupported_beta_body_fields(&mut rendered);
+
+        assert!(
+            rendered.get("betas").is_none(),
+            "betas must not appear in /v1/messages request bodies"
+        );
+        assert_eq!(
+            rendered.get("model").and_then(serde_json::Value::as_str),
+            Some("claude-sonnet-4-6")
+        );
+    }
 }

rust/crates/api/src/providers/mod.rs

@@ -204,6 +204,14 @@ pub fn max_tokens_for_model(model: &str) -> u32 {
     )
 }
 
+/// Returns the effective max output tokens for a model, preferring a plugin
+/// override when present. Falls back to [`max_tokens_for_model`] when the
+/// override is `None`.
+#[must_use]
+pub fn max_tokens_for_model_with_override(model: &str, plugin_override: Option<u32>) -> u32 {
+    plugin_override.unwrap_or_else(|| max_tokens_for_model(model))
+}
+
 #[must_use]
 pub fn model_token_limit(model: &str) -> Option<ModelTokenLimit> {
     let canonical = resolve_model_alias(model);
@@ -258,6 +266,61 @@ fn estimate_serialized_tokens<T: Serialize>(value: &T) -> u32 {
         .map_or(0, |bytes| (bytes.len() / 4 + 1) as u32)
 }
 
+/// Parse a `.env` file body into key/value pairs using a minimal `KEY=VALUE`
+/// grammar. Lines that are blank, start with `#`, or do not contain `=` are
+/// ignored. Surrounding double or single quotes are stripped from the value.
+/// An optional leading `export ` prefix on the key is also stripped so files
+/// shared with shell `source` workflows still parse cleanly.
+pub(crate) fn parse_dotenv(content: &str) -> std::collections::HashMap<String, String> {
+    let mut values = std::collections::HashMap::new();
+    for raw_line in content.lines() {
+        let line = raw_line.trim();
+        if line.is_empty() || line.starts_with('#') {
+            continue;
+        }
+        let Some((raw_key, raw_value)) = line.split_once('=') else {
+            continue;
+        };
+        let trimmed_key = raw_key.trim();
+        let key = trimmed_key
+            .strip_prefix("export ")
+            .map_or(trimmed_key, str::trim)
+            .to_string();
+        if key.is_empty() {
+            continue;
+        }
+        let trimmed_value = raw_value.trim();
+        let unquoted = if (trimmed_value.starts_with('"') && trimmed_value.ends_with('"')
+            || trimmed_value.starts_with('\'') && trimmed_value.ends_with('\''))
+            && trimmed_value.len() >= 2
+        {
+            &trimmed_value[1..trimmed_value.len() - 1]
+        } else {
+            trimmed_value
+        };
+        values.insert(key, unquoted.to_string());
+    }
+    values
+}
+
+/// Load and parse a `.env` file from the given path. Missing files yield
+/// `None` instead of an error so callers can use this as a soft fallback.
+pub(crate) fn load_dotenv_file(
+    path: &std::path::Path,
+) -> Option<std::collections::HashMap<String, String>> {
+    let content = std::fs::read_to_string(path).ok()?;
+    Some(parse_dotenv(&content))
+}
+
+/// Look up `key` in a `.env` file located in the current working directory.
+/// Returns `None` when the file is missing, the key is absent, or the value
+/// is empty.
+pub(crate) fn dotenv_value(key: &str) -> Option<String> {
+    let cwd = std::env::current_dir().ok()?;
+    let values = load_dotenv_file(&cwd.join(".env"))?;
+    values.get(key).filter(|value| !value.is_empty()).cloned()
+}
+
 #[cfg(test)]
 mod tests {
     use serde_json::json;
@@ -268,8 +331,9 @@ mod tests {
     };
 
     use super::{
-        detect_provider_kind, max_tokens_for_model, model_token_limit, preflight_message_request,
-        resolve_model_alias, ProviderKind,
+        detect_provider_kind, load_dotenv_file, max_tokens_for_model,
+        max_tokens_for_model_with_override, model_token_limit, parse_dotenv,
+        preflight_message_request, resolve_model_alias, ProviderKind,
     };
 
     #[test]
@@ -294,6 +358,56 @@ mod tests {
         assert_eq!(max_tokens_for_model("grok-3"), 64_000);
     }
 
+    #[test]
+    fn plugin_config_max_output_tokens_overrides_model_default() {
+        // given
+        let nanos = std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .expect("time should be after epoch")
+            .as_nanos();
+        let root = std::env::temp_dir().join(format!("api-plugin-max-tokens-{nanos}"));
+        let cwd = root.join("project");
+        let home = root.join("home").join(".claw");
+        std::fs::create_dir_all(cwd.join(".claw")).expect("project config dir");
+        std::fs::create_dir_all(&home).expect("home config dir");
+        std::fs::write(
+            home.join("settings.json"),
+            r#"{
+              "plugins": {
+                "maxOutputTokens": 12345
+              }
+            }"#,
+        )
+        .expect("write plugin settings");
+
+        // when
+        let loaded = runtime::ConfigLoader::new(&cwd, &home)
+            .load()
+            .expect("config should load");
+        let plugin_override = loaded.plugins().max_output_tokens();
+        let effective = max_tokens_for_model_with_override("claude-opus-4-6", plugin_override);
+
+        // then
+        assert_eq!(plugin_override, Some(12345));
+        assert_eq!(effective, 12345);
+        assert_ne!(effective, max_tokens_for_model("claude-opus-4-6"));
+
+        std::fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
+    #[test]
+    fn max_tokens_for_model_with_override_falls_back_when_plugin_unset() {
+        // given
+        let plugin_override: Option<u32> = None;
+
+        // when
+        let effective = max_tokens_for_model_with_override("claude-opus-4-6", plugin_override);
+
+        // then
+        assert_eq!(effective, max_tokens_for_model("claude-opus-4-6"));
+        assert_eq!(effective, 32_000);
+    }
+
     #[test]
     fn returns_context_window_metadata_for_supported_models() {
         assert_eq!(
@@ -375,4 +489,85 @@ mod tests {
         preflight_message_request(&request)
             .expect("models without context metadata should skip the guarded preflight");
     }
+
+    #[test]
+    fn parse_dotenv_extracts_keys_handles_comments_quotes_and_export_prefix() {
+        // given
+        let body = "\
+# this is a comment
+
+ANTHROPIC_API_KEY=plain-value
+XAI_API_KEY=\"quoted-value\"
+OPENAI_API_KEY='single-quoted'
+export GROK_API_KEY=exported-value
+   PADDED_KEY  =  padded-value  
+EMPTY_VALUE=
+NO_EQUALS_LINE
+";
+
+        // when
+        let values = parse_dotenv(body);
+
+        // then
+        assert_eq!(
+            values.get("ANTHROPIC_API_KEY").map(String::as_str),
+            Some("plain-value")
+        );
+        assert_eq!(
+            values.get("XAI_API_KEY").map(String::as_str),
+            Some("quoted-value")
+        );
+        assert_eq!(
+            values.get("OPENAI_API_KEY").map(String::as_str),
+            Some("single-quoted")
+        );
+        assert_eq!(
+            values.get("GROK_API_KEY").map(String::as_str),
+            Some("exported-value")
+        );
+        assert_eq!(
+            values.get("PADDED_KEY").map(String::as_str),
+            Some("padded-value")
+        );
+        assert_eq!(values.get("EMPTY_VALUE").map(String::as_str), Some(""));
+        assert!(!values.contains_key("NO_EQUALS_LINE"));
+        assert!(!values.contains_key("# this is a comment"));
+    }
+
+    #[test]
+    fn load_dotenv_file_reads_keys_from_disk_and_returns_none_when_missing() {
+        // given
+        let temp_root = std::env::temp_dir().join(format!(
+            "api-dotenv-test-{}-{}",
+            std::process::id(),
+            std::time::SystemTime::now()
+                .duration_since(std::time::UNIX_EPOCH)
+                .map_or(0, |duration| duration.as_nanos())
+        ));
+        std::fs::create_dir_all(&temp_root).expect("create temp dir");
+        let env_path = temp_root.join(".env");
+        std::fs::write(
+            &env_path,
+            "ANTHROPIC_API_KEY=secret-from-file\n# comment\nXAI_API_KEY=\"xai-secret\"\n",
+        )
+        .expect("write .env");
+        let missing_path = temp_root.join("does-not-exist.env");
+
+        // when
+        let loaded = load_dotenv_file(&env_path).expect("file should load");
+        let missing = load_dotenv_file(&missing_path);
+
+        // then
+        assert_eq!(
+            loaded.get("ANTHROPIC_API_KEY").map(String::as_str),
+            Some("secret-from-file")
+        );
+        assert_eq!(
+            loaded.get("XAI_API_KEY").map(String::as_str),
+            Some("xai-secret")
+        );
+        assert!(missing.is_none());
+
+        let _ = std::fs::remove_dir_all(&temp_root);
+    }
 }

rust/crates/api/src/providers/openai_compat.rs

@@ -1,10 +1,12 @@
 use std::collections::{BTreeMap, VecDeque};
-use std::time::Duration;
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::time::{Duration, SystemTime, UNIX_EPOCH};
 
 use serde::Deserialize;
 use serde_json::{json, Value};
 
 use crate::error::ApiError;
+use crate::http_client::build_http_client_or_default;
 use crate::types::{
     ContentBlockDelta, ContentBlockDeltaEvent, ContentBlockStartEvent, ContentBlockStopEvent,
     InputContentBlock, InputMessage, MessageDelta, MessageDeltaEvent, MessageRequest,
@@ -18,9 +20,9 @@ pub const DEFAULT_XAI_BASE_URL: &str = "https://api.x.ai/v1";
 pub const DEFAULT_OPENAI_BASE_URL: &str = "https://api.openai.com/v1";
 const REQUEST_ID_HEADER: &str = "request-id";
 const ALT_REQUEST_ID_HEADER: &str = "x-request-id";
-const DEFAULT_INITIAL_BACKOFF: Duration = Duration::from_millis(200);
-const DEFAULT_MAX_BACKOFF: Duration = Duration::from_secs(2);
-const DEFAULT_MAX_RETRIES: u32 = 2;
+const DEFAULT_INITIAL_BACKOFF: Duration = Duration::from_secs(1);
+const DEFAULT_MAX_BACKOFF: Duration = Duration::from_secs(128);
+const DEFAULT_MAX_RETRIES: u32 = 8;
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
 pub struct OpenAiCompatConfig {
@@ -81,7 +83,7 @@ impl OpenAiCompatClient {
     #[must_use]
     pub fn new(api_key: impl Into<String>, config: OpenAiCompatConfig) -> Self {
         Self {
-            http: reqwest::Client::new(),
+            http: build_http_client_or_default(),
             api_key: api_key.into(),
             config,
             base_url: read_base_url(config),
@@ -131,7 +133,15 @@ impl OpenAiCompatClient {
         preflight_message_request(&request)?;
         let response = self.send_with_retry(&request).await?;
         let request_id = request_id_from_headers(response.headers());
-        let payload = response.json::<ChatCompletionResponse>().await?;
+        let body = response.text().await.map_err(ApiError::from)?;
+        let payload = serde_json::from_str::<ChatCompletionResponse>(&body).map_err(|error| {
+            ApiError::json_deserialize(
+                self.config.provider_name,
+                &request.model,
+                &body,
+                error,
+            )
+        })?;
         let mut normalized = normalize_response(&request.model, payload)?;
         if normalized.request_id.is_none() {
             normalized.request_id = request_id;
@@ -150,7 +160,10 @@ impl OpenAiCompatClient {
         Ok(MessageStream {
             request_id: request_id_from_headers(response.headers()),
             response,
-            parser: OpenAiSseParser::new(),
+            parser: OpenAiSseParser::with_context(
+                self.config.provider_name,
+                request.model.clone(),
+            ),
             pending: VecDeque::new(),
             done: false,
             state: StreamState::new(request.model.clone()),
@@ -179,7 +192,7 @@ impl OpenAiCompatClient {
                 break retryable_error;
             }
 
-            tokio::time::sleep(self.backoff_for_attempt(attempts)?).await;
+            tokio::time::sleep(self.jittered_backoff_for_attempt(attempts)?).await;
         };
 
         Err(ApiError::RetriesExhausted {
@@ -215,6 +228,37 @@ impl OpenAiCompatClient {
             .checked_mul(multiplier)
             .map_or(self.max_backoff, |delay| delay.min(self.max_backoff)))
     }
+
+    fn jittered_backoff_for_attempt(&self, attempt: u32) -> Result<Duration, ApiError> {
+        let base = self.backoff_for_attempt(attempt)?;
+        Ok(base + jitter_for_base(base))
+    }
+}
+
+/// Process-wide counter that guarantees distinct jitter samples even when
+/// the system clock resolution is coarser than consecutive retry sleeps.
+static JITTER_COUNTER: AtomicU64 = AtomicU64::new(0);
+
+/// Returns a random additive jitter in `[0, base]` to decorrelate retries
+/// from multiple concurrent clients. Entropy is drawn from the nanosecond
+/// wall clock mixed with a monotonic counter and run through a splitmix64
+/// finalizer; adequate for retry jitter (no cryptographic requirement).
+fn jitter_for_base(base: Duration) -> Duration {
+    let base_nanos = u64::try_from(base.as_nanos()).unwrap_or(u64::MAX);
+    if base_nanos == 0 {
+        return Duration::ZERO;
+    }
+    let raw_nanos = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .map(|elapsed| u64::try_from(elapsed.as_nanos()).unwrap_or(u64::MAX))
+        .unwrap_or(0);
+    let tick = JITTER_COUNTER.fetch_add(1, Ordering::Relaxed);
+    let mut mixed = raw_nanos.wrapping_add(tick).wrapping_add(0x9E37_79B9_7F4A_7C15);
+    mixed = (mixed ^ (mixed >> 30)).wrapping_mul(0xBF58_476D_1CE4_E5B9);
+    mixed = (mixed ^ (mixed >> 27)).wrapping_mul(0x94D0_49BB_1331_11EB);
+    mixed ^= mixed >> 31;
+    let jitter_nanos = mixed % base_nanos.saturating_add(1);
+    Duration::from_nanos(jitter_nanos)
 }
 
 impl Provider for OpenAiCompatClient {
@@ -282,11 +326,17 @@ impl MessageStream {
 #[derive(Debug, Default)]
 struct OpenAiSseParser {
     buffer: Vec<u8>,
+    provider: String,
+    model: String,
 }
 
 impl OpenAiSseParser {
-    fn new() -> Self {
-        Self::default()
+    fn with_context(provider: impl Into<String>, model: impl Into<String>) -> Self {
+        Self {
+            buffer: Vec::new(),
+            provider: provider.into(),
+            model: model.into(),
+        }
     }
 
     fn push(&mut self, chunk: &[u8]) -> Result<Vec<ChatCompletionChunk>, ApiError> {
@@ -294,7 +344,7 @@ impl OpenAiSseParser {
         let mut events = Vec::new();
 
         while let Some(frame) = next_sse_frame(&mut self.buffer) {
-            if let Some(event) = parse_sse_frame(&frame)? {
+            if let Some(event) = parse_sse_frame(&frame, &self.provider, &self.model)? {
                 events.push(event);
             }
         }
@@ -835,7 +885,11 @@ fn next_sse_frame(buffer: &mut Vec<u8>) -> Option<String> {
     Some(String::from_utf8_lossy(&frame[..frame_len]).into_owned())
 }
 
-fn parse_sse_frame(frame: &str) -> Result<Option<ChatCompletionChunk>, ApiError> {
+fn parse_sse_frame(
+    frame: &str,
+    provider: &str,
+    model: &str,
+) -> Result<Option<ChatCompletionChunk>, ApiError> {
     let trimmed = frame.trim();
     if trimmed.is_empty() {
         return Ok(None);
@@ -857,15 +911,15 @@ fn parse_sse_frame(frame: &str) -> Result<Option<ChatCompletionChunk>, ApiError>
     if payload == "[DONE]" {
         return Ok(None);
     }
-    serde_json::from_str(&payload)
+    serde_json::from_str::<ChatCompletionChunk>(&payload)
         .map(Some)
-        .map_err(ApiError::from)
+        .map_err(|error| ApiError::json_deserialize(provider, model, &payload, error))
 }
 
 fn read_env_non_empty(key: &str) -> Result<Option<String>, ApiError> {
     match std::env::var(key) {
         Ok(value) if !value.is_empty() => Ok(Some(value)),
-        Ok(_) | Err(std::env::VarError::NotPresent) => Ok(None),
+        Ok(_) | Err(std::env::VarError::NotPresent) => Ok(super::dotenv_value(key)),
         Err(error) => Err(ApiError::from(error)),
     }
 }

rust/crates/api/src/sse.rs

@@ -4,6 +4,8 @@ use crate::types::StreamEvent;
 #[derive(Debug, Default)]
 pub struct SseParser {
     buffer: Vec<u8>,
+    provider: Option<String>,
+    model: Option<String>,
 }
 
 impl SseParser {
@@ -12,12 +14,23 @@ impl SseParser {
         Self::default()
     }
 
+    /// Attach the provider name and model to this parser so that JSON
+    /// deserialization failures within streamed frames carry enough context
+    /// for callers to understand which upstream produced the unparseable
+    /// payload.
+    #[must_use]
+    pub fn with_context(mut self, provider: impl Into<String>, model: impl Into<String>) -> Self {
+        self.provider = Some(provider.into());
+        self.model = Some(model.into());
+        self
+    }
+
     pub fn push(&mut self, chunk: &[u8]) -> Result<Vec<StreamEvent>, ApiError> {
         self.buffer.extend_from_slice(chunk);
         let mut events = Vec::new();
 
         while let Some(frame) = self.next_frame() {
-            if let Some(event) = parse_frame(&frame)? {
+            if let Some(event) = self.parse_frame_with_context(&frame)? {
                 events.push(event);
             }
         }
@@ -31,12 +44,18 @@ impl SseParser {
         }
 
         let trailing = std::mem::take(&mut self.buffer);
-        match parse_frame(&String::from_utf8_lossy(&trailing))? {
+        match self.parse_frame_with_context(&String::from_utf8_lossy(&trailing))? {
             Some(event) => Ok(vec![event]),
             None => Ok(Vec::new()),
         }
     }
 
+    fn parse_frame_with_context(&self, frame: &str) -> Result<Option<StreamEvent>, ApiError> {
+        let provider = self.provider.as_deref().unwrap_or("unknown");
+        let model = self.model.as_deref().unwrap_or("unknown");
+        parse_frame_with_provider(frame, provider, model)
+    }
+
     fn next_frame(&mut self) -> Option<String> {
         let separator = self
             .buffer
@@ -61,6 +80,14 @@ impl SseParser {
 }
 
 pub fn parse_frame(frame: &str) -> Result<Option<StreamEvent>, ApiError> {
+    parse_frame_with_provider(frame, "unknown", "unknown")
+}
+
+pub(crate) fn parse_frame_with_provider(
+    frame: &str,
+    provider: &str,
+    model: &str,
+) -> Result<Option<StreamEvent>, ApiError> {
     let trimmed = frame.trim();
     if trimmed.is_empty() {
         return Ok(None);
@@ -97,7 +124,7 @@ pub fn parse_frame(frame: &str) -> Result<Option<StreamEvent>, ApiError> {
 
     serde_json::from_str::<StreamEvent>(&payload)
         .map(Some)
-        .map_err(ApiError::from)
+        .map_err(|error| ApiError::json_deserialize(provider, model, &payload, error))
 }
 
 #[cfg(test)]
@@ -276,4 +303,28 @@ mod tests {
             ))
         );
     }
+
+    #[test]
+    fn given_message_delta_frame_with_empty_usage_when_parsed_then_usage_defaults_to_zero() {
+        // given
+        let frame = concat!(
+            "event: message_delta\n",
+            "data: {\"type\":\"message_delta\",\"delta\":{\"stop_reason\":\"end_turn\",\"stop_sequence\":null},\"usage\":{}}\n\n"
+        );
+
+        // when
+        let event = parse_frame(frame).expect("frame should parse");
+
+        // then
+        assert_eq!(
+            event,
+            Some(StreamEvent::MessageDelta(crate::types::MessageDeltaEvent {
+                delta: MessageDelta {
+                    stop_reason: Some("end_turn".to_string()),
+                    stop_sequence: None,
+                },
+                usage: Usage::default(),
+            }))
+        );
+    }
 }

rust/crates/api/src/types.rs

@@ -113,6 +113,7 @@ pub struct MessageResponse {
     pub stop_reason: Option<String>,
     #[serde(default)]
     pub stop_sequence: Option<String>,
+    #[serde(default)]
     pub usage: Usage,
     #[serde(default)]
     pub request_id: Option<String>,
@@ -147,13 +148,15 @@ pub enum OutputContentBlock {
     },
 }
 
-#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
 pub struct Usage {
+    #[serde(default)]
     pub input_tokens: u32,
     #[serde(default)]
     pub cache_creation_input_tokens: u32,
     #[serde(default)]
     pub cache_read_input_tokens: u32,
+    #[serde(default)]
     pub output_tokens: u32,
 }
 
@@ -194,6 +197,7 @@ pub struct MessageStartEvent {
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub struct MessageDeltaEvent {
     pub delta: MessageDelta,
+    #[serde(default)]
     pub usage: Usage,
 }
 

rust/crates/api/tests/client_integration.rs

@@ -97,9 +97,9 @@ async fn send_message_posts_json_and_parses_response() {
     assert!(body.get("stream").is_none());
     assert_eq!(body["tools"][0]["name"], json!("get_weather"));
     assert_eq!(body["tool_choice"]["type"], json!("auto"));
-    assert_eq!(
-        body["betas"],
-        json!(["claude-code-20250219", "prompt-caching-scope-2026-01-05"])
+    assert!(
+        body.get("betas").is_none(),
+        "betas must travel via the anthropic-beta header, not the request body"
     );
 }
 
@@ -191,13 +191,9 @@ async fn send_message_applies_request_profile_and_records_telemetry() {
     let body: serde_json::Value =
         serde_json::from_str(&request.body).expect("request body should be json");
     assert_eq!(body["metadata"]["source"], json!("clawd-code"));
-    assert_eq!(
-        body["betas"],
-        json!([
-            "claude-code-20250219",
-            "prompt-caching-scope-2026-01-05",
-            "tools-2026-04-01"
-        ])
+    assert!(
+        body.get("betas").is_none(),
+        "betas must travel via the anthropic-beta header, not the request body"
     );
 
     let events = sink.events();
@@ -276,6 +272,44 @@ async fn send_message_parses_prompt_cache_token_usage_from_response() {
     assert_eq!(response.usage.output_tokens, 4);
 }
 
+#[tokio::test]
+async fn given_empty_usage_object_when_send_message_parses_response_then_usage_defaults_to_zero() {
+    // given
+    let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));
+    let body = concat!(
+        "{",
+        "\"id\":\"msg_empty_usage\",",
+        "\"type\":\"message\",",
+        "\"role\":\"assistant\",",
+        "\"content\":[{\"type\":\"text\",\"text\":\"Hello from Claude\"}],",
+        "\"model\":\"claude-3-7-sonnet-latest\",",
+        "\"stop_reason\":\"end_turn\",",
+        "\"stop_sequence\":null,",
+        "\"usage\":{}",
+        "}"
+    );
+    let server = spawn_server(
+        state,
+        vec![http_response("200 OK", "application/json", body)],
+    )
+    .await;
+    let client = AnthropicClient::new("test-key").with_base_url(server.base_url());
+
+    // when
+    let response = client
+        .send_message(&sample_request(false))
+        .await
+        .expect("response with empty usage object should still parse");
+
+    // then
+    assert_eq!(response.id, "msg_empty_usage");
+    assert_eq!(response.total_tokens(), 0);
+    assert_eq!(response.usage.input_tokens, 0);
+    assert_eq!(response.usage.cache_creation_input_tokens, 0);
+    assert_eq!(response.usage.cache_read_input_tokens, 0);
+    assert_eq!(response.usage.output_tokens, 0);
+}
+
 #[tokio::test]
 #[allow(clippy::await_holding_lock)]
 async fn stream_message_parses_sse_events_with_tool_use() {
@@ -511,6 +545,71 @@ async fn surfaces_retry_exhaustion_for_persistent_retryable_errors() {
     }
 }
 
+#[tokio::test]
+async fn retries_multiple_retryable_failures_with_exponential_backoff_and_jitter() {
+    let state = Arc::new(Mutex::new(Vec::<CapturedRequest>::new()));
+    let server = spawn_server(
+        state.clone(),
+        vec![
+            http_response(
+                "429 Too Many Requests",
+                "application/json",
+                "{\"type\":\"error\",\"error\":{\"type\":\"rate_limit_error\",\"message\":\"slow down\"}}",
+            ),
+            http_response(
+                "500 Internal Server Error",
+                "application/json",
+                "{\"type\":\"error\",\"error\":{\"type\":\"api_error\",\"message\":\"boom\"}}",
+            ),
+            http_response(
+                "503 Service Unavailable",
+                "application/json",
+                "{\"type\":\"error\",\"error\":{\"type\":\"overloaded_error\",\"message\":\"busy\"}}",
+            ),
+            http_response(
+                "429 Too Many Requests",
+                "application/json",
+                "{\"type\":\"error\",\"error\":{\"type\":\"rate_limit_error\",\"message\":\"slow down again\"}}",
+            ),
+            http_response(
+                "503 Service Unavailable",
+                "application/json",
+                "{\"type\":\"error\",\"error\":{\"type\":\"overloaded_error\",\"message\":\"still busy\"}}",
+            ),
+            http_response(
+                "200 OK",
+                "application/json",
+                "{\"id\":\"msg_exp_retry\",\"type\":\"message\",\"role\":\"assistant\",\"content\":[{\"type\":\"text\",\"text\":\"Recovered after 5\"}],\"model\":\"claude-3-7-sonnet-latest\",\"stop_reason\":\"end_turn\",\"stop_sequence\":null,\"usage\":{\"input_tokens\":3,\"output_tokens\":2}}",
+            ),
+        ],
+    )
+    .await;
+
+    let client = ApiClient::new("test-key")
+        .with_base_url(server.base_url())
+        .with_retry_policy(8, Duration::from_millis(1), Duration::from_millis(4));
+    let started_at = std::time::Instant::now();
+
+    let response = client
+        .send_message(&sample_request(false))
+        .await
+        .expect("8-retry policy should absorb 5 retryable failures");
+
+    let elapsed = started_at.elapsed();
+    assert_eq!(response.total_tokens(), 5);
+    assert_eq!(
+        state.lock().await.len(),
+        6,
+        "client should issue 1 original + 5 retry requests before the 200"
+    );
+    // Jittered sleeps are bounded by 2 * max_backoff per retry (base + jitter),
+    // so 5 sleeps fit comfortably below this upper bound with generous slack.
+    assert!(
+        elapsed < Duration::from_secs(5),
+        "retries should complete promptly, took {elapsed:?}"
+    );
+}
+
 #[tokio::test]
 #[allow(clippy::await_holding_lock)]
 async fn send_message_reuses_recent_completion_cache_entries() {

rust/crates/api/tests/proxy_integration.rs

@@ -0,0 +1,173 @@
+use std::ffi::OsString;
+use std::sync::{Mutex, OnceLock};
+
+use api::{build_http_client_with, ProxyConfig};
+
+fn env_lock() -> std::sync::MutexGuard<'static, ()> {
+    static LOCK: OnceLock<Mutex<()>> = OnceLock::new();
+    LOCK.get_or_init(|| Mutex::new(()))
+        .lock()
+        .unwrap_or_else(std::sync::PoisonError::into_inner)
+}
+
+struct EnvVarGuard {
+    key: &'static str,
+    original: Option<OsString>,
+}
+
+impl EnvVarGuard {
+    fn set(key: &'static str, value: Option<&str>) -> Self {
+        let original = std::env::var_os(key);
+        match value {
+            Some(value) => std::env::set_var(key, value),
+            None => std::env::remove_var(key),
+        }
+        Self { key, original }
+    }
+}
+
+impl Drop for EnvVarGuard {
+    fn drop(&mut self) {
+        match &self.original {
+            Some(value) => std::env::set_var(self.key, value),
+            None => std::env::remove_var(self.key),
+        }
+    }
+}
+
+#[test]
+fn proxy_config_from_env_reads_uppercase_proxy_vars() {
+    // given
+    let _lock = env_lock();
+    let _http = EnvVarGuard::set("HTTP_PROXY", Some("http://proxy.corp:3128"));
+    let _https = EnvVarGuard::set("HTTPS_PROXY", Some("http://secure.corp:3129"));
+    let _no = EnvVarGuard::set("NO_PROXY", Some("localhost,127.0.0.1"));
+    let _http_lower = EnvVarGuard::set("http_proxy", None);
+    let _https_lower = EnvVarGuard::set("https_proxy", None);
+    let _no_lower = EnvVarGuard::set("no_proxy", None);
+
+    // when
+    let config = ProxyConfig::from_env();
+
+    // then
+    assert_eq!(config.http_proxy.as_deref(), Some("http://proxy.corp:3128"));
+    assert_eq!(
+        config.https_proxy.as_deref(),
+        Some("http://secure.corp:3129")
+    );
+    assert_eq!(config.no_proxy.as_deref(), Some("localhost,127.0.0.1"));
+    assert!(config.proxy_url.is_none());
+    assert!(!config.is_empty());
+}
+
+#[test]
+fn proxy_config_from_env_reads_lowercase_proxy_vars() {
+    // given
+    let _lock = env_lock();
+    let _http = EnvVarGuard::set("HTTP_PROXY", None);
+    let _https = EnvVarGuard::set("HTTPS_PROXY", None);
+    let _no = EnvVarGuard::set("NO_PROXY", None);
+    let _http_lower = EnvVarGuard::set("http_proxy", Some("http://lower.corp:3128"));
+    let _https_lower = EnvVarGuard::set("https_proxy", Some("http://lower-secure.corp:3129"));
+    let _no_lower = EnvVarGuard::set("no_proxy", Some(".internal"));
+
+    // when
+    let config = ProxyConfig::from_env();
+
+    // then
+    assert_eq!(config.http_proxy.as_deref(), Some("http://lower.corp:3128"));
+    assert_eq!(
+        config.https_proxy.as_deref(),
+        Some("http://lower-secure.corp:3129")
+    );
+    assert_eq!(config.no_proxy.as_deref(), Some(".internal"));
+    assert!(!config.is_empty());
+}
+
+#[test]
+fn proxy_config_from_env_is_empty_when_no_vars_set() {
+    // given
+    let _lock = env_lock();
+    let _http = EnvVarGuard::set("HTTP_PROXY", None);
+    let _https = EnvVarGuard::set("HTTPS_PROXY", None);
+    let _no = EnvVarGuard::set("NO_PROXY", None);
+    let _http_lower = EnvVarGuard::set("http_proxy", None);
+    let _https_lower = EnvVarGuard::set("https_proxy", None);
+    let _no_lower = EnvVarGuard::set("no_proxy", None);
+
+    // when
+    let config = ProxyConfig::from_env();
+
+    // then
+    assert!(config.is_empty());
+    assert!(config.http_proxy.is_none());
+    assert!(config.https_proxy.is_none());
+    assert!(config.no_proxy.is_none());
+}
+
+#[test]
+fn proxy_config_from_env_treats_empty_values_as_unset() {
+    // given
+    let _lock = env_lock();
+    let _http = EnvVarGuard::set("HTTP_PROXY", Some(""));
+    let _https = EnvVarGuard::set("HTTPS_PROXY", Some(""));
+    let _http_lower = EnvVarGuard::set("http_proxy", Some(""));
+    let _https_lower = EnvVarGuard::set("https_proxy", Some(""));
+    let _no = EnvVarGuard::set("NO_PROXY", Some(""));
+    let _no_lower = EnvVarGuard::set("no_proxy", Some(""));
+
+    // when
+    let config = ProxyConfig::from_env();
+
+    // then
+    assert!(config.is_empty());
+}
+
+#[test]
+fn build_client_with_env_proxy_config_succeeds() {
+    // given
+    let _lock = env_lock();
+    let _http = EnvVarGuard::set("HTTP_PROXY", Some("http://proxy.corp:3128"));
+    let _https = EnvVarGuard::set("HTTPS_PROXY", Some("http://secure.corp:3129"));
+    let _no = EnvVarGuard::set("NO_PROXY", Some("localhost"));
+    let _http_lower = EnvVarGuard::set("http_proxy", None);
+    let _https_lower = EnvVarGuard::set("https_proxy", None);
+    let _no_lower = EnvVarGuard::set("no_proxy", None);
+    let config = ProxyConfig::from_env();
+
+    // when
+    let result = build_http_client_with(&config);
+
+    // then
+    assert!(result.is_ok());
+}
+
+#[test]
+fn build_client_with_proxy_url_config_succeeds() {
+    // given
+    let config = ProxyConfig::from_proxy_url("http://unified.corp:3128");
+
+    // when
+    let result = build_http_client_with(&config);
+
+    // then
+    assert!(result.is_ok());
+}
+
+#[test]
+fn proxy_config_from_env_prefers_uppercase_over_lowercase() {
+    // given
+    let _lock = env_lock();
+    let _http_upper = EnvVarGuard::set("HTTP_PROXY", Some("http://upper.corp:3128"));
+    let _http_lower = EnvVarGuard::set("http_proxy", Some("http://lower.corp:3128"));
+    let _https = EnvVarGuard::set("HTTPS_PROXY", None);
+    let _https_lower = EnvVarGuard::set("https_proxy", None);
+    let _no = EnvVarGuard::set("NO_PROXY", None);
+    let _no_lower = EnvVarGuard::set("no_proxy", None);
+
+    // when
+    let config = ProxyConfig::from_env();
+
+    // then
+    assert_eq!(config.http_proxy.as_deref(), Some("http://upper.corp:3128"));
+}

rust/crates/commands/src/lib.rs

@@ -221,8 +221,10 @@ const SLASH_COMMAND_SPECS: &[SlashCommandSpec] = &[
     SlashCommandSpec {
         name: "session",
         aliases: &[],
-        summary: "List, switch, or fork managed local sessions",
-        argument_hint: Some("[list|switch <session-id>|fork [branch-name]]"),
+        summary: "List, switch, fork, or delete managed local sessions",
+        argument_hint: Some(
+            "[list|switch <session-id>|fork [branch-name]|delete <session-id> [--force]]",
+        ),
         resume_supported: false,
     },
     SlashCommandSpec {
@@ -1188,6 +1190,9 @@ pub enum SlashCommand {
     AddDir {
         path: Option<String>,
     },
+    History {
+        count: Option<String>,
+    },
     Unknown(String),
 }
 
@@ -1421,6 +1426,9 @@ pub fn validate_slash_command_input(
         "tag" => SlashCommand::Tag { label: remainder },
         "output-style" => SlashCommand::OutputStyle { style: remainder },
         "add-dir" => SlashCommand::AddDir { path: remainder },
+        "history" => SlashCommand::History {
+            count: optional_single_arg(command, &args, "[count]")?,
+        },
         other => SlashCommand::Unknown(other.to_string()),
     }))
 }
@@ -1520,7 +1528,7 @@ fn parse_session_command(args: &[&str]) -> Result<SlashCommand, SlashCommandPars
             action: Some("list".to_string()),
             target: None,
         }),
-        ["list", ..] => Err(usage_error("session", "[list|switch <session-id>|fork [branch-name]]")),
+        ["list", ..] => Err(usage_error("session", "[list|switch <session-id>|fork [branch-name]|delete <session-id> [--force]]")),
         ["switch"] => Err(usage_error("session switch", "<session-id>")),
         ["switch", target] => Ok(SlashCommand::Session {
             action: Some("switch".to_string()),
@@ -1544,12 +1552,33 @@ fn parse_session_command(args: &[&str]) -> Result<SlashCommand, SlashCommandPars
             "session",
             "/session fork [branch-name]",
         )),
-        [action, ..] => Err(command_error(
+        ["delete"] => Err(usage_error("session delete", "<session-id> [--force]")),
+        ["delete", target] => Ok(SlashCommand::Session {
+            action: Some("delete".to_string()),
+            target: Some((*target).to_string()),
+        }),
+        ["delete", target, "--force"] => Ok(SlashCommand::Session {
+            action: Some("delete-force".to_string()),
+            target: Some((*target).to_string()),
+        }),
+        ["delete", _target, unexpected] => Err(command_error(
             &format!(
-                "Unknown /session action '{action}'. Use list, switch <session-id>, or fork [branch-name]."
+                "Unsupported /session delete flag '{unexpected}'. Use --force to skip confirmation."
             ),
             "session",
-            "/session [list|switch <session-id>|fork [branch-name]]",
+            "/session delete <session-id> [--force]",
+        )),
+        ["delete", ..] => Err(command_error(
+            "Unexpected arguments for /session delete.",
+            "session",
+            "/session delete <session-id> [--force]",
+        )),
+        [action, ..] => Err(command_error(
+            &format!(
+                "Unknown /session action '{action}'. Use list, switch <session-id>, fork [branch-name], or delete <session-id> [--force]."
+            ),
+            "session",
+            "/session [list|switch <session-id>|fork [branch-name]|delete <session-id> [--force]]",
         )),
     }
 }
@@ -1786,24 +1815,29 @@ pub fn resume_supported_slash_commands() -> Vec<&'static SlashCommandSpec> {
 
 fn slash_command_category(name: &str) -> &'static str {
     match name {
-        "help" | "status" | "sandbox" | "model" | "permissions" | "cost" | "resume" | "session"
-        | "version" | "login" | "logout" | "usage" | "stats" | "rename" | "privacy-settings" => {
-            "Session & visibility"
-        }
-        "compact" | "clear" | "config" | "memory" | "init" | "diff" | "commit" | "pr" | "issue"
-        | "export" | "plugin" | "branch" | "add-dir" | "files" | "hooks" | "release-notes" => {
-            "Workspace & git"
-        }
-        "agents" | "skills" | "teleport" | "debug-tool-call" | "mcp" | "context" | "tasks"
-        | "doctor" | "ide" | "desktop" => "Discovery & debugging",
-        "bughunter" | "ultraplan" | "review" | "security-review" | "advisor" | "insights" => {
-            "Analysis & automation"
-        }
-        "theme" | "vim" | "voice" | "color" | "effort" | "fast" | "brief" | "output-style"
-        | "keybindings" | "stickers" => "Appearance & input",
-        "copy" | "share" | "feedback" | "summary" | "tag" | "thinkback" | "plan" | "exit"
-        | "upgrade" | "rewind" => "Communication & control",
-        _ => "Other",
+        "help" | "status" | "cost" | "resume" | "session" | "version" | "login" | "logout"
+        | "usage" | "stats" | "rename" | "clear" | "compact" | "history" | "tokens" | "cache"
+        | "exit" | "summary" | "tag" | "thinkback" | "copy" | "share" | "feedback" | "rewind"
+        | "pin" | "unpin" | "bookmarks" | "context" | "files" | "focus" | "unfocus" | "retry"
+        | "stop" | "undo" => "Session",
+        "diff" | "commit" | "pr" | "issue" | "branch" | "blame" | "log" | "git" | "stash"
+        | "init" | "export" | "plan" | "review" | "security-review" | "bughunter" | "ultraplan"
+        | "teleport" | "refactor" | "fix" | "autofix" | "explain" | "docs" | "perf" | "search"
+        | "references" | "definition" | "hover" | "symbols" | "map" | "web" | "image"
+        | "screenshot" | "paste" | "listen" | "speak" | "test" | "lint" | "build" | "run"
+        | "format" | "parallel" | "multi" | "macro" | "alias" | "templates" | "migrate"
+        | "benchmark" | "cron" | "agent" | "subagent" | "agents" | "skills" | "team" | "plugin"
+        | "mcp" | "hooks" | "tasks" | "advisor" | "insights" | "release-notes" | "chat"
+        | "approve" | "deny" | "allowed-tools" | "add-dir" => "Tools",
+        "model" | "permissions" | "config" | "memory" | "theme" | "vim" | "voice" | "color"
+        | "effort" | "fast" | "brief" | "output-style" | "keybindings" | "privacy-settings"
+        | "stickers" | "language" | "profile" | "max-tokens" | "temperature" | "system-prompt"
+        | "api-key" | "terminal-setup" | "notifications" | "telemetry" | "providers" | "env"
+        | "project" | "reasoning" | "budget" | "rate-limit" | "workspace" | "reset" | "ide"
+        | "desktop" | "upgrade" => "Config",
+        "debug-tool-call" | "doctor" | "sandbox" | "diagnostics" | "tool-details" | "changelog"
+        | "metrics" => "Debug",
+        _ => "Tools",
     }
 }
 
@@ -1912,12 +1946,7 @@ pub fn render_slash_command_help() -> String {
         String::new(),
     ];
 
-    let categories = [
-        "Session & visibility",
-        "Workspace & git",
-        "Discovery & debugging",
-        "Analysis & automation",
-    ];
+    let categories = ["Session", "Tools", "Config", "Debug"];
 
     for category in categories {
         lines.push(category.to_string());
@@ -1930,6 +1959,12 @@ pub fn render_slash_command_help() -> String {
         lines.push(String::new());
     }
 
+    lines.push("Keyboard shortcuts".to_string());
+    lines.push("  Up/Down              Navigate prompt history".to_string());
+    lines.push("  Tab                  Complete commands, modes, and recent sessions".to_string());
+    lines.push("  Ctrl-C               Clear input (or exit on empty prompt)".to_string());
+    lines.push("  Shift+Enter/Ctrl+J   Insert a newline".to_string());
+
     lines
         .into_iter()
         .rev()
@@ -2314,8 +2349,7 @@ pub fn resolve_skill_invocation(
             .unwrap_or_default();
         if !skill_token.is_empty() {
             if let Err(error) = resolve_skill_path(cwd, skill_token) {
-                let mut message =
-                    format!("Unknown skill: {skill_token} ({error})");
+                let mut message = format!("Unknown skill: {skill_token} ({error})");
                 let roots = discover_skill_roots(cwd);
                 if let Ok(available) = load_skills_from_roots(&roots) {
                     let names: Vec<String> = available
@@ -2324,15 +2358,10 @@ pub fn resolve_skill_invocation(
                         .map(|s| s.name.clone())
                         .collect();
                     if !names.is_empty() {
-                        message.push_str(&format!(
-                            "\n  Available skills: {}",
-                            names.join(", ")
-                        ));
+                        message.push_str(&format!("\n  Available skills: {}", names.join(", ")));
                     }
                 }
-                message.push_str(
-                    "\n  Usage: /skills [list|install <path>|help|<skill> [args]]",
-                );
+                message.push_str("\n  Usage: /skills [list|install <path>|help|<skill> [args]]");
                 return Err(message);
             }
         }
@@ -3942,6 +3971,7 @@ pub fn handle_slash_command(
         | SlashCommand::Tag { .. }
         | SlashCommand::OutputStyle { .. }
         | SlashCommand::AddDir { .. }
+        | SlashCommand::History { .. }
         | SlashCommand::Unknown(_) => None,
     }
 }
@@ -4256,6 +4286,47 @@ mod tests {
         );
     }
 
+    #[test]
+    fn parses_history_command_without_count() {
+        // given
+        let input = "/history";
+
+        // when
+        let parsed = SlashCommand::parse(input);
+
+        // then
+        assert_eq!(parsed, Ok(Some(SlashCommand::History { count: None })));
+    }
+
+    #[test]
+    fn parses_history_command_with_numeric_count() {
+        // given
+        let input = "/history 25";
+
+        // when
+        let parsed = SlashCommand::parse(input);
+
+        // then
+        assert_eq!(
+            parsed,
+            Ok(Some(SlashCommand::History {
+                count: Some("25".to_string())
+            }))
+        );
+    }
+
+    #[test]
+    fn rejects_history_with_extra_arguments() {
+        // given
+        let input = "/history 25 extra";
+
+        // when
+        let error = parse_error_message(input);
+
+        // then
+        assert!(error.contains("Usage: /history [count]"));
+    }
+
     #[test]
     fn rejects_unexpected_arguments_for_no_arg_commands() {
         // given
@@ -4297,7 +4368,7 @@ mod tests {
 
         // then
         assert!(error.contains("Usage: /teleport <symbol-or-path>"));
-        assert!(error.contains("  Category         Discovery & debugging"));
+        assert!(error.contains("  Category         Tools"));
     }
 
     #[test]
@@ -4371,10 +4442,10 @@ mod tests {
         let help = render_slash_command_help();
         assert!(help.contains("Start here        /status, /diff, /agents, /skills, /commit"));
         assert!(help.contains("[resume]          also works with --resume SESSION.jsonl"));
-        assert!(help.contains("Session & visibility"));
-        assert!(help.contains("Workspace & git"));
-        assert!(help.contains("Discovery & debugging"));
-        assert!(help.contains("Analysis & automation"));
+        assert!(help.contains("Session"));
+        assert!(help.contains("Tools"));
+        assert!(help.contains("Config"));
+        assert!(help.contains("Debug"));
         assert!(help.contains("/help"));
         assert!(help.contains("/status"));
         assert!(help.contains("/sandbox"));
@@ -4411,6 +4482,53 @@ mod tests {
         assert!(resume_supported_slash_commands().len() >= 39);
     }
 
+    #[test]
+    fn renders_help_with_grouped_categories_and_keyboard_shortcuts() {
+        // given
+        let categories = ["Session", "Tools", "Config", "Debug"];
+
+        // when
+        let help = render_slash_command_help();
+
+        // then
+        for category in categories {
+            assert!(
+                help.contains(category),
+                "expected help to contain category {category}"
+            );
+        }
+        let session_index = help.find("Session").expect("Session header should exist");
+        let tools_index = help.find("Tools").expect("Tools header should exist");
+        let config_index = help.find("Config").expect("Config header should exist");
+        let debug_index = help.find("Debug").expect("Debug header should exist");
+        assert!(session_index < tools_index);
+        assert!(tools_index < config_index);
+        assert!(config_index < debug_index);
+
+        assert!(help.contains("Keyboard shortcuts"));
+        assert!(help.contains("Up/Down              Navigate prompt history"));
+        assert!(help.contains("Tab                  Complete commands, modes, and recent sessions"));
+        assert!(help.contains("Ctrl-C               Clear input (or exit on empty prompt)"));
+        assert!(help.contains("Shift+Enter/Ctrl+J   Insert a newline"));
+
+        // every command should still render with a summary line
+        for spec in slash_command_specs() {
+            let usage = match spec.argument_hint {
+                Some(hint) => format!("/{} {hint}", spec.name),
+                None => format!("/{}", spec.name),
+            };
+            assert!(
+                help.contains(&usage),
+                "expected help to contain command {usage}"
+            );
+            assert!(
+                help.contains(spec.summary),
+                "expected help to contain summary for /{}",
+                spec.name
+            );
+        }
+    }
+
     #[test]
     fn renders_per_command_help_detail() {
         // given
@@ -4423,7 +4541,7 @@ mod tests {
         assert!(help.contains("/plugin"));
         assert!(help.contains("Summary          Manage Claw Code plugins"));
         assert!(help.contains("Aliases          /plugins, /marketplace"));
-        assert!(help.contains("Category         Workspace & git"));
+        assert!(help.contains("Category         Tools"));
     }
 
     #[test]
@@ -4431,7 +4549,7 @@ mod tests {
         let help = render_slash_command_help_detail("mcp").expect("detail help should exist");
         assert!(help.contains("/mcp"));
         assert!(help.contains("Summary          Inspect configured MCP servers"));
-        assert!(help.contains("Category         Discovery & debugging"));
+        assert!(help.contains("Category         Tools"));
         assert!(help.contains("Resume           Supported with --resume SESSION.jsonl"));
     }
 

rust/crates/runtime/Cargo.toml

@@ -13,7 +13,7 @@ regex = "1"
 serde = { version = "1", features = ["derive"] }
 serde_json.workspace = true
 telemetry = { path = "../telemetry" }
-tokio = { version = "1", features = ["io-util", "macros", "process", "rt", "rt-multi-thread", "time"] }
+tokio = { version = "1", features = ["io-std", "io-util", "macros", "process", "rt", "rt-multi-thread", "time"] }
 walkdir = "2"
 
 [lints]

rust/crates/runtime/src/config.rs

@@ -9,6 +9,27 @@ use crate::sandbox::{FilesystemIsolationMode, SandboxConfig};
 /// Schema name advertised by generated settings files.
 pub const CLAW_SETTINGS_SCHEMA_NAME: &str = "SettingsSchema";
 
+/// Top-level settings keys recognized by the runtime configuration loader.
+const KNOWN_TOP_LEVEL_KEYS: &[&str] = &[
+    "$schema",
+    "enabledPlugins",
+    "env",
+    "hooks",
+    "mcpServers",
+    "model",
+    "oauth",
+    "permissionMode",
+    "permissions",
+    "plugins",
+    "sandbox",
+];
+
+/// Deprecated top-level keys mapped to their replacement guidance.
+const DEPRECATED_TOP_LEVEL_KEYS: &[(&str, &str)] = &[
+    ("allowedTools", "permissions.allow"),
+    ("ignorePatterns", "permissions.deny"),
+];
+
 /// Origin of a loaded settings file in the configuration precedence chain.
 #[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
 pub enum ConfigSource {
@@ -48,6 +69,7 @@ pub struct RuntimePluginConfig {
     install_root: Option<String>,
     registry_path: Option<String>,
     bundled_root: Option<String>,
+    max_output_tokens: Option<u32>,
 }
 
 /// Structured feature configuration consumed by runtime subsystems.
@@ -58,9 +80,20 @@ pub struct RuntimeFeatureConfig {
     mcp: McpConfigCollection,
     oauth: Option<OAuthConfig>,
     model: Option<String>,
+    aliases: BTreeMap<String, String>,
     permission_mode: Option<ResolvedPermissionMode>,
     permission_rules: RuntimePermissionRuleConfig,
     sandbox: SandboxConfig,
+    provider_fallbacks: ProviderFallbackConfig,
+}
+
+/// Ordered chain of fallback model identifiers used when the primary
+/// provider returns a retryable failure (429/500/503/etc.). The chain is
+/// strict: each entry is tried in order until one succeeds.
+#[derive(Debug, Clone, PartialEq, Eq, Default)]
+pub struct ProviderFallbackConfig {
+    primary: Option<String>,
+    fallbacks: Vec<String>,
 }
 
 /// Hook command lists grouped by lifecycle stage.
@@ -259,17 +292,33 @@ impl ConfigLoader {
         let mut merged = BTreeMap::new();
         let mut loaded_entries = Vec::new();
         let mut mcp_servers = BTreeMap::new();
+        let mut all_warnings = Vec::new();
 
         for entry in self.discover() {
-            let Some(value) = read_optional_json_object(&entry.path)? else {
+            crate::config_validate::check_unsupported_format(&entry.path)?;
+            let Some(parsed) = read_optional_json_object(&entry.path)? else {
                 continue;
             };
-            validate_optional_hooks_config(&value, &entry.path)?;
-            merge_mcp_servers(&mut mcp_servers, entry.source, &value, &entry.path)?;
-            deep_merge_objects(&mut merged, &value);
+            let validation = crate::config_validate::validate_config_file(
+                &parsed.object,
+                &parsed.source,
+                &entry.path,
+            );
+            if !validation.is_ok() {
+                let first_error = &validation.errors[0];
+                return Err(ConfigError::Parse(first_error.to_string()));
+            }
+            all_warnings.extend(validation.warnings);
+            validate_optional_hooks_config(&parsed.object, &entry.path)?;
+            merge_mcp_servers(&mut mcp_servers, entry.source, &parsed.object, &entry.path)?;
+            deep_merge_objects(&mut merged, &parsed.object);
             loaded_entries.push(entry);
         }
 
+        for warning in &all_warnings {
+            eprintln!("warning: {warning}");
+        }
+
         let merged_value = JsonValue::Object(merged.clone());
 
         let feature_config = RuntimeFeatureConfig {
@@ -280,9 +329,11 @@ impl ConfigLoader {
             },
             oauth: parse_optional_oauth_config(&merged_value, "merged settings.oauth")?,
             model: parse_optional_model(&merged_value),
+            aliases: parse_optional_aliases(&merged_value)?,
             permission_mode: parse_optional_permission_mode(&merged_value)?,
             permission_rules: parse_optional_permission_rules(&merged_value)?,
             sandbox: parse_optional_sandbox_config(&merged_value)?,
+            provider_fallbacks: parse_optional_provider_fallbacks(&merged_value)?,
         };
 
         Ok(RuntimeConfig {
@@ -353,6 +404,11 @@ impl RuntimeConfig {
         self.feature_config.model.as_deref()
     }
 
+    #[must_use]
+    pub fn aliases(&self) -> &BTreeMap<String, String> {
+        &self.feature_config.aliases
+    }
+
     #[must_use]
     pub fn permission_mode(&self) -> Option<ResolvedPermissionMode> {
         self.feature_config.permission_mode
@@ -367,6 +423,11 @@ impl RuntimeConfig {
     pub fn sandbox(&self) -> &SandboxConfig {
         &self.feature_config.sandbox
     }
+
+    #[must_use]
+    pub fn provider_fallbacks(&self) -> &ProviderFallbackConfig {
+        &self.feature_config.provider_fallbacks
+    }
 }
 
 impl RuntimeFeatureConfig {
@@ -407,6 +468,11 @@ impl RuntimeFeatureConfig {
         self.model.as_deref()
     }
 
+    #[must_use]
+    pub fn aliases(&self) -> &BTreeMap<String, String> {
+        &self.aliases
+    }
+
     #[must_use]
     pub fn permission_mode(&self) -> Option<ResolvedPermissionMode> {
         self.permission_mode
@@ -421,6 +487,33 @@ impl RuntimeFeatureConfig {
     pub fn sandbox(&self) -> &SandboxConfig {
         &self.sandbox
     }
+
+    #[must_use]
+    pub fn provider_fallbacks(&self) -> &ProviderFallbackConfig {
+        &self.provider_fallbacks
+    }
+}
+
+impl ProviderFallbackConfig {
+    #[must_use]
+    pub fn new(primary: Option<String>, fallbacks: Vec<String>) -> Self {
+        Self { primary, fallbacks }
+    }
+
+    #[must_use]
+    pub fn primary(&self) -> Option<&str> {
+        self.primary.as_deref()
+    }
+
+    #[must_use]
+    pub fn fallbacks(&self) -> &[String] {
+        &self.fallbacks
+    }
+
+    #[must_use]
+    pub fn is_empty(&self) -> bool {
+        self.fallbacks.is_empty()
+    }
 }
 
 impl RuntimePluginConfig {
@@ -449,6 +542,15 @@ impl RuntimePluginConfig {
         self.bundled_root.as_deref()
     }
 
+    #[must_use]
+    pub fn max_output_tokens(&self) -> Option<u32> {
+        self.max_output_tokens
+    }
+
+    pub fn set_max_output_tokens(&mut self, max_output_tokens: Option<u32>) {
+        self.max_output_tokens = max_output_tokens;
+    }
+
     pub fn set_plugin_state(&mut self, plugin_id: String, enabled: bool) {
         self.enabled_plugins.insert(plugin_id, enabled);
     }
@@ -572,9 +674,13 @@ impl McpServerConfig {
     }
 }
 
-fn read_optional_json_object(
-    path: &Path,
-) -> Result<Option<BTreeMap<String, JsonValue>>, ConfigError> {
+/// Parsed JSON object paired with its raw source text for validation.
+struct ParsedConfigFile {
+    object: BTreeMap<String, JsonValue>,
+    source: String,
+}
+
+fn read_optional_json_object(path: &Path) -> Result<Option<ParsedConfigFile>, ConfigError> {
     let is_legacy_config = path.file_name().and_then(|name| name.to_str()) == Some(".claw.json");
     let contents = match fs::read_to_string(path) {
         Ok(contents) => contents,
@@ -583,7 +689,10 @@ fn read_optional_json_object(
     };
 
     if contents.trim().is_empty() {
-        return Ok(Some(BTreeMap::new()));
+        return Ok(Some(ParsedConfigFile {
+            object: BTreeMap::new(),
+            source: contents,
+        }));
     }
 
     let parsed = match JsonValue::parse(&contents) {
@@ -600,7 +709,10 @@ fn read_optional_json_object(
             path.display()
         )));
     };
-    Ok(Some(object.clone()))
+    Ok(Some(ParsedConfigFile {
+        object: object.clone(),
+        source: contents,
+    }))
 }
 
 fn merge_mcp_servers(
@@ -637,6 +749,13 @@ fn parse_optional_model(root: &JsonValue) -> Option<String> {
         .map(ToOwned::to_owned)
 }
 
+fn parse_optional_aliases(root: &JsonValue) -> Result<BTreeMap<String, String>, ConfigError> {
+    let Some(object) = root.as_object() else {
+        return Ok(BTreeMap::new());
+    };
+    Ok(optional_string_map(object, "aliases", "merged settings")?.unwrap_or_default())
+}
+
 fn parse_optional_hooks_config(root: &JsonValue) -> Result<RuntimeHookConfig, ConfigError> {
     let Some(object) = root.as_object() else {
         return Ok(RuntimeHookConfig::default());
@@ -714,6 +833,7 @@ fn parse_optional_plugin_config(root: &JsonValue) -> Result<RuntimePluginConfig,
         optional_string(plugins, "registryPath", "merged settings.plugins")?.map(str::to_string);
     config.bundled_root =
         optional_string(plugins, "bundledRoot", "merged settings.plugins")?.map(str::to_string);
+    config.max_output_tokens = optional_u32(plugins, "maxOutputTokens", "merged settings.plugins")?;
     Ok(config)
 }
 
@@ -776,6 +896,23 @@ fn parse_optional_sandbox_config(root: &JsonValue) -> Result<SandboxConfig, Conf
     })
 }
 
+fn parse_optional_provider_fallbacks(
+    root: &JsonValue,
+) -> Result<ProviderFallbackConfig, ConfigError> {
+    let Some(object) = root.as_object() else {
+        return Ok(ProviderFallbackConfig::default());
+    };
+    let Some(value) = object.get("providerFallbacks") else {
+        return Ok(ProviderFallbackConfig::default());
+    };
+    let entry = expect_object(value, "merged settings.providerFallbacks")?;
+    let primary =
+        optional_string(entry, "primary", "merged settings.providerFallbacks")?.map(str::to_string);
+    let fallbacks = optional_string_array(entry, "fallbacks", "merged settings.providerFallbacks")?
+        .unwrap_or_default();
+    Ok(ProviderFallbackConfig { primary, fallbacks })
+}
+
 fn parse_filesystem_mode_label(value: &str) -> Result<FilesystemIsolationMode, ConfigError> {
     match value {
         "off" => Ok(FilesystemIsolationMode::Off),
@@ -957,6 +1094,27 @@ fn optional_u16(
     }
 }
 
+fn optional_u32(
+    object: &BTreeMap<String, JsonValue>,
+    key: &str,
+    context: &str,
+) -> Result<Option<u32>, ConfigError> {
+    match object.get(key) {
+        Some(value) => {
+            let Some(number) = value.as_i64() else {
+                return Err(ConfigError::Parse(format!(
+                    "{context}: field {key} must be a non-negative integer"
+                )));
+            };
+            let number = u32::try_from(number).map_err(|_| {
+                ConfigError::Parse(format!("{context}: field {key} is out of range"))
+            })?;
+            Ok(Some(number))
+        }
+        None => Ok(None),
+    }
+}
+
 fn optional_u64(
     object: &BTreeMap<String, JsonValue>,
     key: &str,
@@ -1247,6 +1405,66 @@ mod tests {
         fs::remove_dir_all(root).expect("cleanup temp dir");
     }
 
+    #[test]
+    fn parses_provider_fallbacks_chain_with_primary_and_ordered_fallbacks() {
+        // given
+        let root = temp_dir();
+        let cwd = root.join("project");
+        let home = root.join("home").join(".claw");
+        fs::create_dir_all(cwd.join(".claw")).expect("project config dir");
+        fs::create_dir_all(&home).expect("home config dir");
+        fs::write(
+            home.join("settings.json"),
+            r#"{
+              "providerFallbacks": {
+                "primary": "claude-opus-4-6",
+                "fallbacks": ["grok-3", "grok-3-mini"]
+              }
+            }"#,
+        )
+        .expect("write provider fallback settings");
+
+        // when
+        let loaded = ConfigLoader::new(&cwd, &home)
+            .load()
+            .expect("config should load");
+
+        // then
+        let chain = loaded.provider_fallbacks();
+        assert_eq!(chain.primary(), Some("claude-opus-4-6"));
+        assert_eq!(
+            chain.fallbacks(),
+            &["grok-3".to_string(), "grok-3-mini".to_string()]
+        );
+        assert!(!chain.is_empty());
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
+    #[test]
+    fn provider_fallbacks_default_is_empty_when_unset() {
+        // given
+        let root = temp_dir();
+        let cwd = root.join("project");
+        let home = root.join("home").join(".claw");
+        fs::create_dir_all(&home).expect("home config dir");
+        fs::create_dir_all(&cwd).expect("project dir");
+        fs::write(home.join("settings.json"), "{}").expect("write empty settings");
+
+        // when
+        let loaded = ConfigLoader::new(&cwd, &home)
+            .load()
+            .expect("config should load");
+
+        // then
+        let chain = loaded.provider_fallbacks();
+        assert_eq!(chain.primary(), None);
+        assert!(chain.fallbacks().is_empty());
+        assert!(chain.is_empty());
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
     #[test]
     fn parses_typed_mcp_and_oauth_config() {
         let root = temp_dir();
@@ -1493,6 +1711,49 @@ mod tests {
         fs::remove_dir_all(root).expect("cleanup temp dir");
     }
 
+    #[test]
+    fn parses_user_defined_model_aliases_from_settings() {
+        // given
+        let root = temp_dir();
+        let cwd = root.join("project");
+        let home = root.join("home").join(".claw");
+        fs::create_dir_all(cwd.join(".claw")).expect("project config dir");
+        fs::create_dir_all(&home).expect("home config dir");
+
+        fs::write(
+            home.join("settings.json"),
+            r#"{"aliases":{"fast":"claude-haiku-4-5-20251213","smart":"claude-opus-4-6"}}"#,
+        )
+        .expect("write user settings");
+        fs::write(
+            cwd.join(".claw").join("settings.local.json"),
+            r#"{"aliases":{"smart":"claude-sonnet-4-6","cheap":"grok-3-mini"}}"#,
+        )
+        .expect("write local settings");
+
+        // when
+        let loaded = ConfigLoader::new(&cwd, &home)
+            .load()
+            .expect("config should load");
+
+        // then
+        let aliases = loaded.aliases();
+        assert_eq!(
+            aliases.get("fast").map(String::as_str),
+            Some("claude-haiku-4-5-20251213")
+        );
+        assert_eq!(
+            aliases.get("smart").map(String::as_str),
+            Some("claude-sonnet-4-6")
+        );
+        assert_eq!(
+            aliases.get("cheap").map(String::as_str),
+            Some("grok-3-mini")
+        );
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
     #[test]
     fn empty_settings_file_loads_defaults() {
         // given
@@ -1574,12 +1835,13 @@ mod tests {
             .load()
             .expect_err("config should fail");
 
-        // then
+        // then — config validation now catches the mixed array before the hooks parser
         let rendered = error.to_string();
-        assert!(rendered.contains(&format!(
-            "{}: hooks: field PreToolUse must contain only strings",
-            project_settings.display()
-        )));
+        assert!(
+            rendered.contains("hooks.PreToolUse")
+                && rendered.contains("must be an array of strings"),
+            "expected validation error for hooks.PreToolUse, got: {rendered}"
+        );
         assert!(!rendered.contains("merged settings.hooks"));
 
         fs::remove_dir_all(root).expect("cleanup temp dir");
@@ -1645,4 +1907,140 @@ mod tests {
         assert!(config.state_for("missing", true));
         assert!(!config.state_for("missing", false));
     }
+
+    #[test]
+    fn validates_unknown_top_level_keys_with_line_and_field_name() {
+        // given
+        let root = temp_dir();
+        let cwd = root.join("project");
+        let home = root.join("home").join(".claw");
+        let user_settings = home.join("settings.json");
+        fs::create_dir_all(&home).expect("home config dir");
+        fs::create_dir_all(&cwd).expect("project dir");
+        fs::write(
+            &user_settings,
+            "{\n  \"model\": \"opus\",\n  \"telemetry\": true\n}\n",
+        )
+        .expect("write user settings");
+
+        // when
+        let error = ConfigLoader::new(&cwd, &home)
+            .load()
+            .expect_err("config should fail");
+
+        // then
+        let rendered = error.to_string();
+        assert!(
+            rendered.contains(&format!("{}:3:", user_settings.display())),
+            "error should include file path and line number, got: {rendered}"
+        );
+        assert!(
+            rendered.contains("unknown field telemetry"),
+            "error should name the offending field, got: {rendered}"
+        );
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
+    #[test]
+    fn validates_deprecated_top_level_keys_with_replacement_guidance() {
+        // given
+        let root = temp_dir();
+        let cwd = root.join("project");
+        let home = root.join("home").join(".claw");
+        let user_settings = home.join("settings.json");
+        fs::create_dir_all(&home).expect("home config dir");
+        fs::create_dir_all(&cwd).expect("project dir");
+        fs::write(
+            &user_settings,
+            "{\n  \"model\": \"opus\",\n  \"allowedTools\": [\"Read\"]\n}\n",
+        )
+        .expect("write user settings");
+
+        // when
+        let error = ConfigLoader::new(&cwd, &home)
+            .load()
+            .expect_err("config should fail");
+
+        // then
+        let rendered = error.to_string();
+        assert!(
+            rendered.contains(&format!("{}:3:", user_settings.display())),
+            "error should include file path and line number, got: {rendered}"
+        );
+        assert!(
+            rendered.contains("deprecated field allowedTools"),
+            "error should call out the deprecated field, got: {rendered}"
+        );
+        assert!(
+            rendered.contains("permissions.allow"),
+            "error should mention the replacement field, got: {rendered}"
+        );
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
+    #[test]
+    fn validates_wrong_type_for_known_field_with_field_path() {
+        // given
+        let root = temp_dir();
+        let cwd = root.join("project");
+        let home = root.join("home").join(".claw");
+        let user_settings = home.join("settings.json");
+        fs::create_dir_all(&home).expect("home config dir");
+        fs::create_dir_all(&cwd).expect("project dir");
+        fs::write(
+            &user_settings,
+            "{\n  \"hooks\": {\n    \"PreToolUse\": \"not-an-array\"\n  }\n}\n",
+        )
+        .expect("write user settings");
+
+        // when
+        let error = ConfigLoader::new(&cwd, &home)
+            .load()
+            .expect_err("config should fail");
+
+        // then
+        let rendered = error.to_string();
+        assert!(
+            rendered.contains(&format!("{}: hooks", user_settings.display())),
+            "error should include file path and field path, got: {rendered}"
+        );
+        assert!(
+            rendered.contains("PreToolUse must be an array"),
+            "error should describe the type mismatch, got: {rendered}"
+        );
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
+    #[test]
+    fn unknown_top_level_key_suggests_closest_match() {
+        // given
+        let root = temp_dir();
+        let cwd = root.join("project");
+        let home = root.join("home").join(".claw");
+        let user_settings = home.join("settings.json");
+        fs::create_dir_all(&home).expect("home config dir");
+        fs::create_dir_all(&cwd).expect("project dir");
+        fs::write(&user_settings, "{\n  \"modle\": \"opus\"\n}\n").expect("write user settings");
+
+        // when
+        let error = ConfigLoader::new(&cwd, &home)
+            .load()
+            .expect_err("config should fail");
+
+        // then
+        let rendered = error.to_string();
+        assert!(
+            rendered.contains("unknown field modle"),
+            "error should name the offending field, got: {rendered}"
+        );
+        assert!(
+            rendered.contains("did you mean model?"),
+            "error should suggest the closest known key, got: {rendered}"
+        );
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
 }

rust/crates/runtime/src/config_validate.rs

@@ -0,0 +1,887 @@
+use std::collections::BTreeMap;
+use std::path::Path;
+
+use crate::config::ConfigError;
+use crate::json::JsonValue;
+
+/// Diagnostic emitted when a config file contains a suspect field.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ConfigDiagnostic {
+    pub path: String,
+    pub field: String,
+    pub line: Option<usize>,
+    pub kind: DiagnosticKind,
+}
+
+/// Classification of the diagnostic.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum DiagnosticKind {
+    UnknownKey {
+        suggestion: Option<String>,
+    },
+    WrongType {
+        expected: &'static str,
+        got: &'static str,
+    },
+    Deprecated {
+        replacement: &'static str,
+    },
+}
+
+impl std::fmt::Display for ConfigDiagnostic {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let location = self
+            .line
+            .map_or_else(String::new, |line| format!(" (line {line})"));
+        match &self.kind {
+            DiagnosticKind::UnknownKey { suggestion: None } => {
+                write!(f, "{}: unknown key \"{}\"{location}", self.path, self.field)
+            }
+            DiagnosticKind::UnknownKey {
+                suggestion: Some(hint),
+            } => {
+                write!(
+                    f,
+                    "{}: unknown key \"{}\"{location}. Did you mean \"{}\"?",
+                    self.path, self.field, hint
+                )
+            }
+            DiagnosticKind::WrongType { expected, got } => {
+                write!(
+                    f,
+                    "{}: field \"{}\" must be {expected}, got {got}{location}",
+                    self.path, self.field
+                )
+            }
+            DiagnosticKind::Deprecated { replacement } => {
+                write!(
+                    f,
+                    "{}: field \"{}\" is deprecated{location}. Use \"{replacement}\" instead",
+                    self.path, self.field
+                )
+            }
+        }
+    }
+}
+
+/// Result of validating a single config file.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct ValidationResult {
+    pub errors: Vec<ConfigDiagnostic>,
+    pub warnings: Vec<ConfigDiagnostic>,
+}
+
+impl ValidationResult {
+    #[must_use]
+    pub fn is_ok(&self) -> bool {
+        self.errors.is_empty()
+    }
+
+    fn merge(&mut self, other: Self) {
+        self.errors.extend(other.errors);
+        self.warnings.extend(other.warnings);
+    }
+}
+
+// ---- known-key schema ----
+
+/// Expected type for a config field.
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+enum FieldType {
+    String,
+    Bool,
+    Object,
+    StringArray,
+    Number,
+}
+
+impl FieldType {
+    fn label(self) -> &'static str {
+        match self {
+            Self::String => "a string",
+            Self::Bool => "a boolean",
+            Self::Object => "an object",
+            Self::StringArray => "an array of strings",
+            Self::Number => "a number",
+        }
+    }
+
+    fn matches(self, value: &JsonValue) -> bool {
+        match self {
+            Self::String => value.as_str().is_some(),
+            Self::Bool => value.as_bool().is_some(),
+            Self::Object => value.as_object().is_some(),
+            Self::StringArray => value
+                .as_array()
+                .is_some_and(|arr| arr.iter().all(|v| v.as_str().is_some())),
+            Self::Number => value.as_i64().is_some(),
+        }
+    }
+}
+
+fn json_type_label(value: &JsonValue) -> &'static str {
+    match value {
+        JsonValue::Null => "null",
+        JsonValue::Bool(_) => "a boolean",
+        JsonValue::Number(_) => "a number",
+        JsonValue::String(_) => "a string",
+        JsonValue::Array(_) => "an array",
+        JsonValue::Object(_) => "an object",
+    }
+}
+
+struct FieldSpec {
+    name: &'static str,
+    expected: FieldType,
+}
+
+struct DeprecatedField {
+    name: &'static str,
+    replacement: &'static str,
+}
+
+const TOP_LEVEL_FIELDS: &[FieldSpec] = &[
+    FieldSpec {
+        name: "$schema",
+        expected: FieldType::String,
+    },
+    FieldSpec {
+        name: "model",
+        expected: FieldType::String,
+    },
+    FieldSpec {
+        name: "hooks",
+        expected: FieldType::Object,
+    },
+    FieldSpec {
+        name: "permissions",
+        expected: FieldType::Object,
+    },
+    FieldSpec {
+        name: "permissionMode",
+        expected: FieldType::String,
+    },
+    FieldSpec {
+        name: "mcpServers",
+        expected: FieldType::Object,
+    },
+    FieldSpec {
+        name: "oauth",
+        expected: FieldType::Object,
+    },
+    FieldSpec {
+        name: "enabledPlugins",
+        expected: FieldType::Object,
+    },
+    FieldSpec {
+        name: "plugins",
+        expected: FieldType::Object,
+    },
+    FieldSpec {
+        name: "sandbox",
+        expected: FieldType::Object,
+    },
+    FieldSpec {
+        name: "env",
+        expected: FieldType::Object,
+    },
+];
+
+const HOOKS_FIELDS: &[FieldSpec] = &[
+    FieldSpec {
+        name: "PreToolUse",
+        expected: FieldType::StringArray,
+    },
+    FieldSpec {
+        name: "PostToolUse",
+        expected: FieldType::StringArray,
+    },
+    FieldSpec {
+        name: "PostToolUseFailure",
+        expected: FieldType::StringArray,
+    },
+];
+
+const PERMISSIONS_FIELDS: &[FieldSpec] = &[
+    FieldSpec {
+        name: "defaultMode",
+        expected: FieldType::String,
+    },
+    FieldSpec {
+        name: "allow",
+        expected: FieldType::StringArray,
+    },
+    FieldSpec {
+        name: "deny",
+        expected: FieldType::StringArray,
+    },
+    FieldSpec {
+        name: "ask",
+        expected: FieldType::StringArray,
+    },
+];
+
+const PLUGINS_FIELDS: &[FieldSpec] = &[
+    FieldSpec {
+        name: "enabled",
+        expected: FieldType::Object,
+    },
+    FieldSpec {
+        name: "externalDirectories",
+        expected: FieldType::StringArray,
+    },
+    FieldSpec {
+        name: "installRoot",
+        expected: FieldType::String,
+    },
+    FieldSpec {
+        name: "registryPath",
+        expected: FieldType::String,
+    },
+    FieldSpec {
+        name: "bundledRoot",
+        expected: FieldType::String,
+    },
+    FieldSpec {
+        name: "maxOutputTokens",
+        expected: FieldType::Number,
+    },
+];
+
+const SANDBOX_FIELDS: &[FieldSpec] = &[
+    FieldSpec {
+        name: "enabled",
+        expected: FieldType::Bool,
+    },
+    FieldSpec {
+        name: "namespaceRestrictions",
+        expected: FieldType::Bool,
+    },
+    FieldSpec {
+        name: "networkIsolation",
+        expected: FieldType::Bool,
+    },
+    FieldSpec {
+        name: "filesystemMode",
+        expected: FieldType::String,
+    },
+    FieldSpec {
+        name: "allowedMounts",
+        expected: FieldType::StringArray,
+    },
+];
+
+const OAUTH_FIELDS: &[FieldSpec] = &[
+    FieldSpec {
+        name: "clientId",
+        expected: FieldType::String,
+    },
+    FieldSpec {
+        name: "authorizeUrl",
+        expected: FieldType::String,
+    },
+    FieldSpec {
+        name: "tokenUrl",
+        expected: FieldType::String,
+    },
+    FieldSpec {
+        name: "callbackPort",
+        expected: FieldType::Number,
+    },
+    FieldSpec {
+        name: "manualRedirectUrl",
+        expected: FieldType::String,
+    },
+    FieldSpec {
+        name: "scopes",
+        expected: FieldType::StringArray,
+    },
+];
+
+const DEPRECATED_FIELDS: &[DeprecatedField] = &[
+    DeprecatedField {
+        name: "permissionMode",
+        replacement: "permissions.defaultMode",
+    },
+    DeprecatedField {
+        name: "enabledPlugins",
+        replacement: "plugins.enabled",
+    },
+];
+
+// ---- line-number resolution ----
+
+/// Find the 1-based line number where a JSON key first appears in the raw source.
+fn find_key_line(source: &str, key: &str) -> Option<usize> {
+    // Search for `"key"` followed by optional whitespace and a colon.
+    let needle = format!("\"{key}\"");
+    let mut search_start = 0;
+    while let Some(offset) = source[search_start..].find(&needle) {
+        let absolute = search_start + offset;
+        let after = absolute + needle.len();
+        // Verify the next non-whitespace char is `:` to confirm this is a key, not a value.
+        if source[after..].chars().find(|ch| !ch.is_ascii_whitespace()) == Some(':') {
+            return Some(source[..absolute].chars().filter(|&ch| ch == '\n').count() + 1);
+        }
+        search_start = after;
+    }
+    None
+}
+
+// ---- core validation ----
+
+fn validate_object_keys(
+    object: &BTreeMap<String, JsonValue>,
+    known_fields: &[FieldSpec],
+    prefix: &str,
+    source: &str,
+    path_display: &str,
+) -> ValidationResult {
+    let mut result = ValidationResult {
+        errors: Vec::new(),
+        warnings: Vec::new(),
+    };
+
+    let known_names: Vec<&str> = known_fields.iter().map(|f| f.name).collect();
+
+    for (key, value) in object {
+        let field_path = if prefix.is_empty() {
+            key.clone()
+        } else {
+            format!("{prefix}.{key}")
+        };
+
+        if let Some(spec) = known_fields.iter().find(|f| f.name == key) {
+            // Type check.
+            if !spec.expected.matches(value) {
+                result.errors.push(ConfigDiagnostic {
+                    path: path_display.to_string(),
+                    field: field_path,
+                    line: find_key_line(source, key),
+                    kind: DiagnosticKind::WrongType {
+                        expected: spec.expected.label(),
+                        got: json_type_label(value),
+                    },
+                });
+            }
+        } else {
+            // Unknown key.
+            let suggestion = suggest_field(key, &known_names);
+            result.errors.push(ConfigDiagnostic {
+                path: path_display.to_string(),
+                field: field_path,
+                line: find_key_line(source, key),
+                kind: DiagnosticKind::UnknownKey { suggestion },
+            });
+        }
+    }
+
+    result
+}
+
+fn suggest_field(input: &str, candidates: &[&str]) -> Option<String> {
+    let input_lower = input.to_ascii_lowercase();
+    candidates
+        .iter()
+        .filter_map(|candidate| {
+            let distance = simple_edit_distance(&input_lower, &candidate.to_ascii_lowercase());
+            (distance <= 3).then_some((distance, *candidate))
+        })
+        .min_by_key(|(distance, _)| *distance)
+        .map(|(_, name)| name.to_string())
+}
+
+fn simple_edit_distance(left: &str, right: &str) -> usize {
+    if left.is_empty() {
+        return right.len();
+    }
+    if right.is_empty() {
+        return left.len();
+    }
+    let right_chars: Vec<char> = right.chars().collect();
+    let mut previous: Vec<usize> = (0..=right_chars.len()).collect();
+    let mut current = vec![0; right_chars.len() + 1];
+
+    for (left_index, left_char) in left.chars().enumerate() {
+        current[0] = left_index + 1;
+        for (right_index, right_char) in right_chars.iter().enumerate() {
+            let cost = usize::from(left_char != *right_char);
+            current[right_index + 1] = (previous[right_index + 1] + 1)
+                .min(current[right_index] + 1)
+                .min(previous[right_index] + cost);
+        }
+        previous.clone_from(&current);
+    }
+
+    previous[right_chars.len()]
+}
+
+/// Validate a parsed config file's keys and types against the known schema.
+///
+/// Returns diagnostics (errors and deprecation warnings) without blocking the load.
+pub fn validate_config_file(
+    object: &BTreeMap<String, JsonValue>,
+    source: &str,
+    file_path: &Path,
+) -> ValidationResult {
+    let path_display = file_path.display().to_string();
+    let mut result = validate_object_keys(object, TOP_LEVEL_FIELDS, "", source, &path_display);
+
+    // Check deprecated fields.
+    for deprecated in DEPRECATED_FIELDS {
+        if object.contains_key(deprecated.name) {
+            result.warnings.push(ConfigDiagnostic {
+                path: path_display.clone(),
+                field: deprecated.name.to_string(),
+                line: find_key_line(source, deprecated.name),
+                kind: DiagnosticKind::Deprecated {
+                    replacement: deprecated.replacement,
+                },
+            });
+        }
+    }
+
+    // Validate known nested objects.
+    if let Some(hooks) = object.get("hooks").and_then(JsonValue::as_object) {
+        result.merge(validate_object_keys(
+            hooks,
+            HOOKS_FIELDS,
+            "hooks",
+            source,
+            &path_display,
+        ));
+    }
+    if let Some(permissions) = object.get("permissions").and_then(JsonValue::as_object) {
+        result.merge(validate_object_keys(
+            permissions,
+            PERMISSIONS_FIELDS,
+            "permissions",
+            source,
+            &path_display,
+        ));
+    }
+    if let Some(plugins) = object.get("plugins").and_then(JsonValue::as_object) {
+        result.merge(validate_object_keys(
+            plugins,
+            PLUGINS_FIELDS,
+            "plugins",
+            source,
+            &path_display,
+        ));
+    }
+    if let Some(sandbox) = object.get("sandbox").and_then(JsonValue::as_object) {
+        result.merge(validate_object_keys(
+            sandbox,
+            SANDBOX_FIELDS,
+            "sandbox",
+            source,
+            &path_display,
+        ));
+    }
+    if let Some(oauth) = object.get("oauth").and_then(JsonValue::as_object) {
+        result.merge(validate_object_keys(
+            oauth,
+            OAUTH_FIELDS,
+            "oauth",
+            source,
+            &path_display,
+        ));
+    }
+
+    result
+}
+
+/// Check whether a file path uses an unsupported config format (e.g. TOML).
+pub fn check_unsupported_format(file_path: &Path) -> Result<(), ConfigError> {
+    if let Some(ext) = file_path.extension().and_then(|e| e.to_str()) {
+        if ext.eq_ignore_ascii_case("toml") {
+            return Err(ConfigError::Parse(format!(
+                "{}: TOML config files are not supported. Use JSON (settings.json) instead",
+                file_path.display()
+            )));
+        }
+    }
+    Ok(())
+}
+
+/// Format all diagnostics into a human-readable report.
+#[must_use]
+pub fn format_diagnostics(result: &ValidationResult) -> String {
+    let mut lines = Vec::new();
+    for warning in &result.warnings {
+        lines.push(format!("warning: {warning}"));
+    }
+    for error in &result.errors {
+        lines.push(format!("error: {error}"));
+    }
+    lines.join("\n")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::path::PathBuf;
+
+    fn test_path() -> PathBuf {
+        PathBuf::from("/test/settings.json")
+    }
+
+    #[test]
+    fn detects_unknown_top_level_key() {
+        // given
+        let source = r#"{"model": "opus", "unknownField": true}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.errors.len(), 1);
+        assert_eq!(result.errors[0].field, "unknownField");
+        assert!(matches!(
+            result.errors[0].kind,
+            DiagnosticKind::UnknownKey { .. }
+        ));
+    }
+
+    #[test]
+    fn detects_wrong_type_for_model() {
+        // given
+        let source = r#"{"model": 123}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.errors.len(), 1);
+        assert_eq!(result.errors[0].field, "model");
+        assert!(matches!(
+            result.errors[0].kind,
+            DiagnosticKind::WrongType {
+                expected: "a string",
+                got: "a number"
+            }
+        ));
+    }
+
+    #[test]
+    fn detects_deprecated_permission_mode() {
+        // given
+        let source = r#"{"permissionMode": "plan"}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.warnings.len(), 1);
+        assert_eq!(result.warnings[0].field, "permissionMode");
+        assert!(matches!(
+            result.warnings[0].kind,
+            DiagnosticKind::Deprecated {
+                replacement: "permissions.defaultMode"
+            }
+        ));
+    }
+
+    #[test]
+    fn detects_deprecated_enabled_plugins() {
+        // given
+        let source = r#"{"enabledPlugins": {"tool-guard@builtin": true}}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.warnings.len(), 1);
+        assert_eq!(result.warnings[0].field, "enabledPlugins");
+        assert!(matches!(
+            result.warnings[0].kind,
+            DiagnosticKind::Deprecated {
+                replacement: "plugins.enabled"
+            }
+        ));
+    }
+
+    #[test]
+    fn reports_line_number_for_unknown_key() {
+        // given
+        let source = "{\n  \"model\": \"opus\",\n  \"badKey\": true\n}";
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.errors.len(), 1);
+        assert_eq!(result.errors[0].line, Some(3));
+        assert_eq!(result.errors[0].field, "badKey");
+    }
+
+    #[test]
+    fn reports_line_number_for_wrong_type() {
+        // given
+        let source = "{\n  \"model\": 42\n}";
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.errors.len(), 1);
+        assert_eq!(result.errors[0].line, Some(2));
+    }
+
+    #[test]
+    fn validates_nested_hooks_keys() {
+        // given
+        let source = r#"{"hooks": {"PreToolUse": ["cmd"], "BadHook": ["x"]}}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.errors.len(), 1);
+        assert_eq!(result.errors[0].field, "hooks.BadHook");
+    }
+
+    #[test]
+    fn validates_nested_permissions_keys() {
+        // given
+        let source = r#"{"permissions": {"allow": ["Read"], "denyAll": true}}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.errors.len(), 1);
+        assert_eq!(result.errors[0].field, "permissions.denyAll");
+    }
+
+    #[test]
+    fn validates_nested_sandbox_keys() {
+        // given
+        let source = r#"{"sandbox": {"enabled": true, "containerMode": "strict"}}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.errors.len(), 1);
+        assert_eq!(result.errors[0].field, "sandbox.containerMode");
+    }
+
+    #[test]
+    fn validates_nested_plugins_keys() {
+        // given
+        let source = r#"{"plugins": {"installRoot": "/tmp", "autoUpdate": true}}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.errors.len(), 1);
+        assert_eq!(result.errors[0].field, "plugins.autoUpdate");
+    }
+
+    #[test]
+    fn validates_nested_oauth_keys() {
+        // given
+        let source = r#"{"oauth": {"clientId": "abc", "secret": "hidden"}}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.errors.len(), 1);
+        assert_eq!(result.errors[0].field, "oauth.secret");
+    }
+
+    #[test]
+    fn valid_config_produces_no_diagnostics() {
+        // given
+        let source = r#"{
+  "model": "opus",
+  "hooks": {"PreToolUse": ["guard"]},
+  "permissions": {"defaultMode": "plan", "allow": ["Read"]},
+  "mcpServers": {},
+  "sandbox": {"enabled": false}
+}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert!(result.is_ok());
+        assert!(result.warnings.is_empty());
+    }
+
+    #[test]
+    fn suggests_close_field_name() {
+        // given
+        let source = r#"{"modle": "opus"}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.errors.len(), 1);
+        match &result.errors[0].kind {
+            DiagnosticKind::UnknownKey {
+                suggestion: Some(s),
+            } => assert_eq!(s, "model"),
+            other => panic!("expected suggestion, got {other:?}"),
+        }
+    }
+
+    #[test]
+    fn format_diagnostics_includes_all_entries() {
+        // given
+        let source = r#"{"permissionMode": "plan", "badKey": 1}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+        let result = validate_config_file(object, source, &test_path());
+
+        // when
+        let output = format_diagnostics(&result);
+
+        // then
+        assert!(output.contains("warning:"));
+        assert!(output.contains("error:"));
+        assert!(output.contains("badKey"));
+        assert!(output.contains("permissionMode"));
+    }
+
+    #[test]
+    fn check_unsupported_format_rejects_toml() {
+        // given
+        let path = PathBuf::from("/home/.claw/settings.toml");
+
+        // when
+        let result = check_unsupported_format(&path);
+
+        // then
+        assert!(result.is_err());
+        let message = result.unwrap_err().to_string();
+        assert!(message.contains("TOML"));
+        assert!(message.contains("settings.toml"));
+    }
+
+    #[test]
+    fn check_unsupported_format_allows_json() {
+        // given
+        let path = PathBuf::from("/home/.claw/settings.json");
+
+        // when / then
+        assert!(check_unsupported_format(&path).is_ok());
+    }
+
+    #[test]
+    fn wrong_type_in_nested_sandbox_field() {
+        // given
+        let source = r#"{"sandbox": {"enabled": "yes"}}"#;
+        let parsed = JsonValue::parse(source).expect("valid json");
+        let object = parsed.as_object().expect("object");
+
+        // when
+        let result = validate_config_file(object, source, &test_path());
+
+        // then
+        assert_eq!(result.errors.len(), 1);
+        assert_eq!(result.errors[0].field, "sandbox.enabled");
+        assert!(matches!(
+            result.errors[0].kind,
+            DiagnosticKind::WrongType {
+                expected: "a boolean",
+                got: "a string"
+            }
+        ));
+    }
+
+    #[test]
+    fn display_format_unknown_key_with_line() {
+        // given
+        let diag = ConfigDiagnostic {
+            path: "/test/settings.json".to_string(),
+            field: "badKey".to_string(),
+            line: Some(5),
+            kind: DiagnosticKind::UnknownKey { suggestion: None },
+        };
+
+        // when
+        let output = diag.to_string();
+
+        // then
+        assert_eq!(
+            output,
+            r#"/test/settings.json: unknown key "badKey" (line 5)"#
+        );
+    }
+
+    #[test]
+    fn display_format_wrong_type_with_line() {
+        // given
+        let diag = ConfigDiagnostic {
+            path: "/test/settings.json".to_string(),
+            field: "model".to_string(),
+            line: Some(2),
+            kind: DiagnosticKind::WrongType {
+                expected: "a string",
+                got: "a number",
+            },
+        };
+
+        // when
+        let output = diag.to_string();
+
+        // then
+        assert_eq!(
+            output,
+            r#"/test/settings.json: field "model" must be a string, got a number (line 2)"#
+        );
+    }
+
+    #[test]
+    fn display_format_deprecated_with_line() {
+        // given
+        let diag = ConfigDiagnostic {
+            path: "/test/settings.json".to_string(),
+            field: "permissionMode".to_string(),
+            line: Some(3),
+            kind: DiagnosticKind::Deprecated {
+                replacement: "permissions.defaultMode",
+            },
+        };
+
+        // when
+        let output = diag.to_string();
+
+        // then
+        assert_eq!(
+            output,
+            r#"/test/settings.json: field "permissionMode" is deprecated (line 3). Use "permissions.defaultMode" instead"#
+        );
+    }
+}

rust/crates/runtime/src/conversation.rs

@@ -504,6 +504,10 @@ where
         &self.session
     }
 
+    pub fn session_mut(&mut self) -> &mut Session {
+        &mut self.session
+    }
+
     #[must_use]
     pub fn fork_session(&self, branch_name: Option<String>) -> Session {
         self.session.fork(branch_name)
@@ -890,6 +894,7 @@ mod tests {
                 current_date: "2026-03-31".to_string(),
                 git_status: None,
                 git_diff: None,
+                git_context: None,
                 instruction_files: Vec::new(),
             })
             .with_os("linux", "6.8")

rust/crates/runtime/src/git_context.rs

@@ -0,0 +1,324 @@
+use std::path::Path;
+use std::process::Command;
+
+/// A single git commit entry from the log.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct GitCommitEntry {
+    pub hash: String,
+    pub subject: String,
+}
+
+/// Git-aware context gathered at startup for injection into the system prompt.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct GitContext {
+    pub branch: Option<String>,
+    pub recent_commits: Vec<GitCommitEntry>,
+    pub staged_files: Vec<String>,
+}
+
+const MAX_RECENT_COMMITS: usize = 5;
+
+impl GitContext {
+    /// Detect the git context from the given working directory.
+    ///
+    /// Returns `None` when the directory is not inside a git repository.
+    #[must_use]
+    pub fn detect(cwd: &Path) -> Option<Self> {
+        // Quick gate: is this a git repo at all?
+        let rev_parse = Command::new("git")
+            .args(["rev-parse", "--is-inside-work-tree"])
+            .current_dir(cwd)
+            .output()
+            .ok()?;
+        if !rev_parse.status.success() {
+            return None;
+        }
+
+        Some(Self {
+            branch: read_branch(cwd),
+            recent_commits: read_recent_commits(cwd),
+            staged_files: read_staged_files(cwd),
+        })
+    }
+
+    /// Render a human-readable summary suitable for system-prompt injection.
+    #[must_use]
+    pub fn render(&self) -> String {
+        let mut lines = Vec::new();
+
+        if let Some(branch) = &self.branch {
+            lines.push(format!("Git branch: {branch}"));
+        }
+
+        if !self.recent_commits.is_empty() {
+            lines.push(String::new());
+            lines.push("Recent commits:".to_string());
+            for entry in &self.recent_commits {
+                lines.push(format!("  {} {}", entry.hash, entry.subject));
+            }
+        }
+
+        if !self.staged_files.is_empty() {
+            lines.push(String::new());
+            lines.push("Staged files:".to_string());
+            for file in &self.staged_files {
+                lines.push(format!("  {file}"));
+            }
+        }
+
+        lines.join("\n")
+    }
+}
+
+fn read_branch(cwd: &Path) -> Option<String> {
+    let output = Command::new("git")
+        .args(["rev-parse", "--abbrev-ref", "HEAD"])
+        .current_dir(cwd)
+        .output()
+        .ok()?;
+    if !output.status.success() {
+        return None;
+    }
+    let branch = String::from_utf8(output.stdout).ok()?;
+    let trimmed = branch.trim();
+    if trimmed.is_empty() || trimmed == "HEAD" {
+        None
+    } else {
+        Some(trimmed.to_string())
+    }
+}
+
+fn read_recent_commits(cwd: &Path) -> Vec<GitCommitEntry> {
+    let output = Command::new("git")
+        .args([
+            "--no-optional-locks",
+            "log",
+            "--oneline",
+            "-n",
+            &MAX_RECENT_COMMITS.to_string(),
+            "--no-decorate",
+        ])
+        .current_dir(cwd)
+        .output()
+        .ok();
+    let Some(output) = output else {
+        return Vec::new();
+    };
+    if !output.status.success() {
+        return Vec::new();
+    }
+    let stdout = String::from_utf8(output.stdout).unwrap_or_default();
+    stdout
+        .lines()
+        .filter_map(|line| {
+            let line = line.trim();
+            if line.is_empty() {
+                return None;
+            }
+            let (hash, subject) = line.split_once(' ')?;
+            Some(GitCommitEntry {
+                hash: hash.to_string(),
+                subject: subject.to_string(),
+            })
+        })
+        .collect()
+}
+
+fn read_staged_files(cwd: &Path) -> Vec<String> {
+    let output = Command::new("git")
+        .args(["--no-optional-locks", "diff", "--cached", "--name-only"])
+        .current_dir(cwd)
+        .output()
+        .ok();
+    let Some(output) = output else {
+        return Vec::new();
+    };
+    if !output.status.success() {
+        return Vec::new();
+    }
+    let stdout = String::from_utf8(output.stdout).unwrap_or_default();
+    stdout
+        .lines()
+        .filter(|line| !line.trim().is_empty())
+        .map(|line| line.trim().to_string())
+        .collect()
+}
+
+#[cfg(test)]
+mod tests {
+    use super::{GitCommitEntry, GitContext};
+    use std::fs;
+    use std::process::Command;
+    use std::time::{SystemTime, UNIX_EPOCH};
+
+    fn temp_dir(label: &str) -> std::path::PathBuf {
+        let nanos = SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .expect("time should be after epoch")
+            .as_nanos();
+        std::env::temp_dir().join(format!("runtime-git-context-{label}-{nanos}"))
+    }
+
+    fn env_lock() -> std::sync::MutexGuard<'static, ()> {
+        crate::test_env_lock()
+    }
+
+    fn ensure_valid_cwd() {
+        if std::env::current_dir().is_err() {
+            std::env::set_current_dir(env!("CARGO_MANIFEST_DIR"))
+                .expect("test cwd should be recoverable");
+        }
+    }
+
+    #[test]
+    fn returns_none_for_non_git_directory() {
+        // given
+        let _guard = env_lock();
+        ensure_valid_cwd();
+        let root = temp_dir("non-git");
+        fs::create_dir_all(&root).expect("create dir");
+
+        // when
+        let context = GitContext::detect(&root);
+
+        // then
+        assert!(context.is_none());
+        fs::remove_dir_all(root).expect("cleanup");
+    }
+
+    #[test]
+    fn detects_branch_name_and_commits() {
+        // given
+        let _guard = env_lock();
+        ensure_valid_cwd();
+        let root = temp_dir("branch-commits");
+        fs::create_dir_all(&root).expect("create dir");
+        git(&root, &["init", "--quiet", "--initial-branch=main"]);
+        git(&root, &["config", "user.email", "tests@example.com"]);
+        git(&root, &["config", "user.name", "Git Context Tests"]);
+        fs::write(root.join("a.txt"), "a\n").expect("write a");
+        git(&root, &["add", "a.txt"]);
+        git(&root, &["commit", "-m", "first commit", "--quiet"]);
+        fs::write(root.join("b.txt"), "b\n").expect("write b");
+        git(&root, &["add", "b.txt"]);
+        git(&root, &["commit", "-m", "second commit", "--quiet"]);
+
+        // when
+        let context = GitContext::detect(&root).expect("should detect git repo");
+
+        // then
+        assert_eq!(context.branch.as_deref(), Some("main"));
+        assert_eq!(context.recent_commits.len(), 2);
+        assert_eq!(context.recent_commits[0].subject, "second commit");
+        assert_eq!(context.recent_commits[1].subject, "first commit");
+        assert!(context.staged_files.is_empty());
+        fs::remove_dir_all(root).expect("cleanup");
+    }
+
+    #[test]
+    fn detects_staged_files() {
+        // given
+        let _guard = env_lock();
+        ensure_valid_cwd();
+        let root = temp_dir("staged");
+        fs::create_dir_all(&root).expect("create dir");
+        git(&root, &["init", "--quiet", "--initial-branch=main"]);
+        git(&root, &["config", "user.email", "tests@example.com"]);
+        git(&root, &["config", "user.name", "Git Context Tests"]);
+        fs::write(root.join("init.txt"), "init\n").expect("write init");
+        git(&root, &["add", "init.txt"]);
+        git(&root, &["commit", "-m", "initial", "--quiet"]);
+        fs::write(root.join("staged.txt"), "staged\n").expect("write staged");
+        git(&root, &["add", "staged.txt"]);
+
+        // when
+        let context = GitContext::detect(&root).expect("should detect git repo");
+
+        // then
+        assert_eq!(context.staged_files, vec!["staged.txt"]);
+        fs::remove_dir_all(root).expect("cleanup");
+    }
+
+    #[test]
+    fn render_formats_all_sections() {
+        // given
+        let context = GitContext {
+            branch: Some("feat/test".to_string()),
+            recent_commits: vec![
+                GitCommitEntry {
+                    hash: "abc1234".to_string(),
+                    subject: "add feature".to_string(),
+                },
+                GitCommitEntry {
+                    hash: "def5678".to_string(),
+                    subject: "fix bug".to_string(),
+                },
+            ],
+            staged_files: vec!["src/main.rs".to_string()],
+        };
+
+        // when
+        let rendered = context.render();
+
+        // then
+        assert!(rendered.contains("Git branch: feat/test"));
+        assert!(rendered.contains("abc1234 add feature"));
+        assert!(rendered.contains("def5678 fix bug"));
+        assert!(rendered.contains("src/main.rs"));
+    }
+
+    #[test]
+    fn render_omits_empty_sections() {
+        // given
+        let context = GitContext {
+            branch: Some("main".to_string()),
+            recent_commits: Vec::new(),
+            staged_files: Vec::new(),
+        };
+
+        // when
+        let rendered = context.render();
+
+        // then
+        assert!(rendered.contains("Git branch: main"));
+        assert!(!rendered.contains("Recent commits:"));
+        assert!(!rendered.contains("Staged files:"));
+    }
+
+    #[test]
+    fn limits_to_five_recent_commits() {
+        // given
+        let _guard = env_lock();
+        ensure_valid_cwd();
+        let root = temp_dir("five-commits");
+        fs::create_dir_all(&root).expect("create dir");
+        git(&root, &["init", "--quiet", "--initial-branch=main"]);
+        git(&root, &["config", "user.email", "tests@example.com"]);
+        git(&root, &["config", "user.name", "Git Context Tests"]);
+        for i in 1..=8 {
+            let name = format!("file{i}.txt");
+            fs::write(root.join(&name), format!("{i}\n")).expect("write file");
+            git(&root, &["add", &name]);
+            git(&root, &["commit", "-m", &format!("commit {i}"), "--quiet"]);
+        }
+
+        // when
+        let context = GitContext::detect(&root).expect("should detect git repo");
+
+        // then
+        assert_eq!(context.recent_commits.len(), 5);
+        assert_eq!(context.recent_commits[0].subject, "commit 8");
+        assert_eq!(context.recent_commits[4].subject, "commit 4");
+        fs::remove_dir_all(root).expect("cleanup");
+    }
+
+    fn git(cwd: &std::path::Path, args: &[&str]) {
+        let status = Command::new("git")
+            .args(args)
+            .current_dir(cwd)
+            .output()
+            .unwrap_or_else(|_| panic!("git {args:?} should run"))
+            .status;
+        assert!(status.success(), "git {args:?} failed");
+    }
+}

rust/crates/runtime/src/lib.rs

@@ -10,8 +10,10 @@ mod bootstrap;
 pub mod branch_lock;
 mod compact;
 mod config;
+pub mod config_validate;
 mod conversation;
 mod file_ops;
+mod git_context;
 pub mod green_contract;
 mod hooks;
 mod json;
@@ -20,6 +22,7 @@ pub mod lsp_client;
 mod mcp;
 mod mcp_client;
 pub mod mcp_lifecycle_hardened;
+pub mod mcp_server;
 mod mcp_stdio;
 pub mod mcp_tool_bridge;
 mod oauth;
@@ -32,9 +35,10 @@ pub mod recovery_recipes;
 mod remote;
 pub mod sandbox;
 mod session;
-#[cfg(test)]
-mod session_control;
+pub mod session_control;
+pub use session_control::SessionStore;
 mod sse;
+pub mod stale_base;
 pub mod stale_branch;
 pub mod summary_compression;
 pub mod task_packet;
@@ -52,12 +56,16 @@ pub use compact::{
     compact_session, estimate_session_tokens, format_compact_summary,
     get_compact_continuation_message, should_compact, CompactionConfig, CompactionResult,
 };
+pub use config_validate::{
+    check_unsupported_format, format_diagnostics, validate_config_file, ConfigDiagnostic,
+    DiagnosticKind, ValidationResult,
+};
 pub use config::{
     ConfigEntry, ConfigError, ConfigLoader, ConfigSource, McpConfigCollection,
     McpManagedProxyServerConfig, McpOAuthConfig, McpRemoteServerConfig, McpSdkServerConfig,
     McpServerConfig, McpStdioServerConfig, McpTransport, McpWebSocketServerConfig, OAuthConfig,
-    ResolvedPermissionMode, RuntimeConfig, RuntimeFeatureConfig, RuntimeHookConfig,
-    RuntimePermissionRuleConfig, RuntimePluginConfig, ScopedMcpServerConfig,
+    ProviderFallbackConfig, ResolvedPermissionMode, RuntimeConfig, RuntimeFeatureConfig,
+    RuntimeHookConfig, RuntimePermissionRuleConfig, RuntimePluginConfig, ScopedMcpServerConfig,
     CLAW_SETTINGS_SCHEMA_NAME,
 };
 pub use conversation::{
@@ -65,6 +73,7 @@ pub use conversation::{
     ConversationRuntime, PromptCacheEvent, RuntimeError, StaticToolExecutor, ToolError,
     ToolExecutor, TurnSummary,
 };
+pub use git_context::{GitCommitEntry, GitContext};
 pub use file_ops::{
     edit_file, glob_search, grep_search, read_file, write_file, EditFileOutput, GlobSearchOutput,
     GrepSearchInput, GrepSearchOutput, ReadFileOutput, StructuredPatchHunk, TextFilePayload,
@@ -89,6 +98,7 @@ pub use mcp_lifecycle_hardened::{
     McpDegradedReport, McpErrorSurface, McpFailedServer, McpLifecyclePhase, McpLifecycleState,
     McpLifecycleValidator, McpPhaseResult,
 };
+pub use mcp_server::{McpServer, McpServerSpec, ToolCallHandler, MCP_SERVER_PROTOCOL_VERSION};
 pub use mcp_stdio::{
     spawn_mcp_stdio_process, JsonRpcError, JsonRpcId, JsonRpcRequest, JsonRpcResponse,
     ManagedMcpTool, McpDiscoveryFailure, McpInitializeClientInfo, McpInitializeParams,
@@ -138,9 +148,13 @@ pub use sandbox::{
 };
 pub use session::{
     ContentBlock, ConversationMessage, MessageRole, Session, SessionCompaction, SessionError,
-    SessionFork,
+    SessionFork, SessionPromptEntry,
 };
 pub use sse::{IncrementalSseParser, SseEvent};
+pub use stale_base::{
+    check_base_commit, format_stale_base_warning, read_claw_base_file, resolve_expected_base,
+    BaseCommitSource, BaseCommitState,
+};
 pub use stale_branch::{
     apply_policy, check_freshness, BranchFreshness, StaleBranchAction, StaleBranchEvent,
     StaleBranchPolicy,

rust/crates/runtime/src/mcp_server.rs

@@ -0,0 +1,442 @@
+//! Minimal Model Context Protocol (MCP) server.
+//!
+//! Implements a newline-safe, LSP-framed JSON-RPC server over stdio that
+//! answers `initialize`, `tools/list`, and `tools/call` requests. The framing
+//! matches the client transport implemented in [`crate::mcp_stdio`] so this
+//! server can be driven by either an external MCP client (e.g. Claude
+//! Desktop) or `claw`'s own [`McpServerManager`](crate::McpServerManager).
+//!
+//! The server is intentionally small: it exposes a list of pre-built
+//! [`McpTool`] descriptors and delegates `tools/call` to a caller-supplied
+//! handler. Tool execution itself lives in the `tools` crate; this module is
+//! purely the transport + dispatch loop.
+//!
+//! [`McpTool`]: crate::mcp_stdio::McpTool
+
+use std::io;
+
+use serde_json::{json, Value as JsonValue};
+use tokio::io::{
+    stdin, stdout, AsyncBufReadExt, AsyncReadExt, AsyncWriteExt, BufReader, Stdin, Stdout,
+};
+
+use crate::mcp_stdio::{
+    JsonRpcError, JsonRpcId, JsonRpcRequest, JsonRpcResponse, McpInitializeResult,
+    McpInitializeServerInfo, McpListToolsResult, McpTool, McpToolCallContent, McpToolCallParams,
+    McpToolCallResult,
+};
+
+/// Protocol version the server advertises during `initialize`.
+///
+/// Matches the version used by the built-in client in
+/// [`crate::mcp_stdio`], so the two stay in lockstep.
+pub const MCP_SERVER_PROTOCOL_VERSION: &str = "2025-03-26";
+
+/// Synchronous handler invoked for every `tools/call` request.
+///
+/// Returning `Ok(text)` yields a single `text` content block and
+/// `isError: false`. Returning `Err(message)` yields a `text` block with the
+/// error and `isError: true`, mirroring the error-surfacing convention used
+/// elsewhere in claw.
+pub type ToolCallHandler =
+    Box<dyn Fn(&str, &JsonValue) -> Result<String, String> + Send + Sync + 'static>;
+
+/// Configuration for an [`McpServer`] instance.
+///
+/// Named `McpServerSpec` rather than `McpServerConfig` to avoid colliding
+/// with the existing client-side [`crate::config::McpServerConfig`] that
+/// describes *remote* MCP servers the runtime connects to.
+pub struct McpServerSpec {
+    /// Name advertised in the `serverInfo` field of the `initialize` response.
+    pub server_name: String,
+    /// Version advertised in the `serverInfo` field of the `initialize`
+    /// response.
+    pub server_version: String,
+    /// Tool descriptors returned for `tools/list`.
+    pub tools: Vec<McpTool>,
+    /// Handler invoked for `tools/call`.
+    pub tool_handler: ToolCallHandler,
+}
+
+/// Minimal MCP stdio server.
+///
+/// The server runs a blocking read/dispatch/write loop over the current
+/// process's stdin/stdout, terminating cleanly when the peer closes the
+/// stream.
+pub struct McpServer {
+    spec: McpServerSpec,
+    stdin: BufReader<Stdin>,
+    stdout: Stdout,
+}
+
+impl McpServer {
+    #[must_use]
+    pub fn new(spec: McpServerSpec) -> Self {
+        Self {
+            spec,
+            stdin: BufReader::new(stdin()),
+            stdout: stdout(),
+        }
+    }
+
+    /// Runs the server until the client closes stdin.
+    ///
+    /// Returns `Ok(())` on clean EOF; any other I/O error is propagated so
+    /// callers can log and exit non-zero.
+    pub async fn run(&mut self) -> io::Result<()> {
+        loop {
+            let Some(payload) = read_frame(&mut self.stdin).await? else {
+                return Ok(());
+            };
+
+            // Requests and notifications share a wire format; the absence of
+            // `id` distinguishes notifications, which must never receive a
+            // response.
+            let message: JsonValue = match serde_json::from_slice(&payload) {
+                Ok(value) => value,
+                Err(error) => {
+                    // Parse error with null id per JSON-RPC 2.0 §4.2.
+                    let response = JsonRpcResponse::<JsonValue> {
+                        jsonrpc: "2.0".to_string(),
+                        id: JsonRpcId::Null,
+                        result: None,
+                        error: Some(JsonRpcError {
+                            code: -32700,
+                            message: format!("parse error: {error}"),
+                            data: None,
+                        }),
+                    };
+                    write_response(&mut self.stdout, &response).await?;
+                    continue;
+                }
+            };
+
+            if message.get("id").is_none() {
+                // Notification: dispatch for side effects only (e.g. log),
+                // but send no reply.
+                continue;
+            }
+
+            let request: JsonRpcRequest<JsonValue> = match serde_json::from_value(message) {
+                Ok(request) => request,
+                Err(error) => {
+                    let response = JsonRpcResponse::<JsonValue> {
+                        jsonrpc: "2.0".to_string(),
+                        id: JsonRpcId::Null,
+                        result: None,
+                        error: Some(JsonRpcError {
+                            code: -32600,
+                            message: format!("invalid request: {error}"),
+                            data: None,
+                        }),
+                    };
+                    write_response(&mut self.stdout, &response).await?;
+                    continue;
+                }
+            };
+
+            let response = self.dispatch(request);
+            write_response(&mut self.stdout, &response).await?;
+        }
+    }
+
+    fn dispatch(&self, request: JsonRpcRequest<JsonValue>) -> JsonRpcResponse<JsonValue> {
+        let id = request.id.clone();
+        match request.method.as_str() {
+            "initialize" => self.handle_initialize(id),
+            "tools/list" => self.handle_tools_list(id),
+            "tools/call" => self.handle_tools_call(id, request.params),
+            other => JsonRpcResponse {
+                jsonrpc: "2.0".to_string(),
+                id,
+                result: None,
+                error: Some(JsonRpcError {
+                    code: -32601,
+                    message: format!("method not found: {other}"),
+                    data: None,
+                }),
+            },
+        }
+    }
+
+    fn handle_initialize(&self, id: JsonRpcId) -> JsonRpcResponse<JsonValue> {
+        let result = McpInitializeResult {
+            protocol_version: MCP_SERVER_PROTOCOL_VERSION.to_string(),
+            capabilities: json!({ "tools": {} }),
+            server_info: McpInitializeServerInfo {
+                name: self.spec.server_name.clone(),
+                version: self.spec.server_version.clone(),
+            },
+        };
+        JsonRpcResponse {
+            jsonrpc: "2.0".to_string(),
+            id,
+            result: serde_json::to_value(result).ok(),
+            error: None,
+        }
+    }
+
+    fn handle_tools_list(&self, id: JsonRpcId) -> JsonRpcResponse<JsonValue> {
+        let result = McpListToolsResult {
+            tools: self.spec.tools.clone(),
+            next_cursor: None,
+        };
+        JsonRpcResponse {
+            jsonrpc: "2.0".to_string(),
+            id,
+            result: serde_json::to_value(result).ok(),
+            error: None,
+        }
+    }
+
+    fn handle_tools_call(
+        &self,
+        id: JsonRpcId,
+        params: Option<JsonValue>,
+    ) -> JsonRpcResponse<JsonValue> {
+        let Some(params) = params else {
+            return invalid_params_response(id, "missing params for tools/call");
+        };
+        let call: McpToolCallParams = match serde_json::from_value(params) {
+            Ok(value) => value,
+            Err(error) => {
+                return invalid_params_response(id, &format!("invalid tools/call params: {error}"));
+            }
+        };
+        let arguments = call.arguments.unwrap_or_else(|| json!({}));
+        let tool_result = (self.spec.tool_handler)(&call.name, &arguments);
+        let (text, is_error) = match tool_result {
+            Ok(text) => (text, false),
+            Err(message) => (message, true),
+        };
+        let mut data = std::collections::BTreeMap::new();
+        data.insert("text".to_string(), JsonValue::String(text));
+        let call_result = McpToolCallResult {
+            content: vec![McpToolCallContent {
+                kind: "text".to_string(),
+                data,
+            }],
+            structured_content: None,
+            is_error: Some(is_error),
+            meta: None,
+        };
+        JsonRpcResponse {
+            jsonrpc: "2.0".to_string(),
+            id,
+            result: serde_json::to_value(call_result).ok(),
+            error: None,
+        }
+    }
+}
+
+fn invalid_params_response(id: JsonRpcId, message: &str) -> JsonRpcResponse<JsonValue> {
+    JsonRpcResponse {
+        jsonrpc: "2.0".to_string(),
+        id,
+        result: None,
+        error: Some(JsonRpcError {
+            code: -32602,
+            message: message.to_string(),
+            data: None,
+        }),
+    }
+}
+
+/// Reads a single LSP-framed JSON-RPC payload from `reader`.
+///
+/// Returns `Ok(None)` on clean EOF before any header bytes have been read,
+/// matching how [`crate::mcp_stdio::McpStdioProcess`] treats stream closure.
+async fn read_frame(reader: &mut BufReader<Stdin>) -> io::Result<Option<Vec<u8>>> {
+    let mut content_length: Option<usize> = None;
+    let mut first_header = true;
+    loop {
+        let mut line = String::new();
+        let bytes_read = reader.read_line(&mut line).await?;
+        if bytes_read == 0 {
+            if first_header {
+                return Ok(None);
+            }
+            return Err(io::Error::new(
+                io::ErrorKind::UnexpectedEof,
+                "MCP stdio stream closed while reading headers",
+            ));
+        }
+        first_header = false;
+        if line == "\r\n" || line == "\n" {
+            break;
+        }
+        let header = line.trim_end_matches(['\r', '\n']);
+        if let Some((name, value)) = header.split_once(':') {
+            if name.trim().eq_ignore_ascii_case("Content-Length") {
+                let parsed = value
+                    .trim()
+                    .parse::<usize>()
+                    .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))?;
+                content_length = Some(parsed);
+            }
+        }
+    }
+
+    let content_length = content_length.ok_or_else(|| {
+        io::Error::new(io::ErrorKind::InvalidData, "missing Content-Length header")
+    })?;
+    let mut payload = vec![0_u8; content_length];
+    reader.read_exact(&mut payload).await?;
+    Ok(Some(payload))
+}
+
+async fn write_response(
+    stdout: &mut Stdout,
+    response: &JsonRpcResponse<JsonValue>,
+) -> io::Result<()> {
+    let body = serde_json::to_vec(response)
+        .map_err(|error| io::Error::new(io::ErrorKind::InvalidData, error))?;
+    let header = format!("Content-Length: {}\r\n\r\n", body.len());
+    stdout.write_all(header.as_bytes()).await?;
+    stdout.write_all(&body).await?;
+    stdout.flush().await
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn dispatch_initialize_returns_server_info() {
+        let server = McpServer {
+            spec: McpServerSpec {
+                server_name: "test".to_string(),
+                server_version: "9.9.9".to_string(),
+                tools: Vec::new(),
+                tool_handler: Box::new(|_, _| Ok(String::new())),
+            },
+            stdin: BufReader::new(stdin()),
+            stdout: stdout(),
+        };
+        let request = JsonRpcRequest::<JsonValue> {
+            jsonrpc: "2.0".to_string(),
+            id: JsonRpcId::Number(1),
+            method: "initialize".to_string(),
+            params: None,
+        };
+        let response = server.dispatch(request);
+        assert_eq!(response.id, JsonRpcId::Number(1));
+        assert!(response.error.is_none());
+        let result = response.result.expect("initialize result");
+        assert_eq!(result["protocolVersion"], MCP_SERVER_PROTOCOL_VERSION);
+        assert_eq!(result["serverInfo"]["name"], "test");
+        assert_eq!(result["serverInfo"]["version"], "9.9.9");
+    }
+
+    #[test]
+    fn dispatch_tools_list_returns_registered_tools() {
+        let tool = McpTool {
+            name: "echo".to_string(),
+            description: Some("Echo".to_string()),
+            input_schema: Some(json!({"type": "object"})),
+            annotations: None,
+            meta: None,
+        };
+        let server = McpServer {
+            spec: McpServerSpec {
+                server_name: "test".to_string(),
+                server_version: "0.0.0".to_string(),
+                tools: vec![tool.clone()],
+                tool_handler: Box::new(|_, _| Ok(String::new())),
+            },
+            stdin: BufReader::new(stdin()),
+            stdout: stdout(),
+        };
+        let request = JsonRpcRequest::<JsonValue> {
+            jsonrpc: "2.0".to_string(),
+            id: JsonRpcId::Number(2),
+            method: "tools/list".to_string(),
+            params: None,
+        };
+        let response = server.dispatch(request);
+        assert!(response.error.is_none());
+        let result = response.result.expect("tools/list result");
+        assert_eq!(result["tools"][0]["name"], "echo");
+    }
+
+    #[test]
+    fn dispatch_tools_call_wraps_handler_output() {
+        let server = McpServer {
+            spec: McpServerSpec {
+                server_name: "test".to_string(),
+                server_version: "0.0.0".to_string(),
+                tools: Vec::new(),
+                tool_handler: Box::new(|name, args| {
+                    Ok(format!("called {name} with {args}"))
+                }),
+            },
+            stdin: BufReader::new(stdin()),
+            stdout: stdout(),
+        };
+        let request = JsonRpcRequest::<JsonValue> {
+            jsonrpc: "2.0".to_string(),
+            id: JsonRpcId::Number(3),
+            method: "tools/call".to_string(),
+            params: Some(json!({
+                "name": "echo",
+                "arguments": {"text": "hi"}
+            })),
+        };
+        let response = server.dispatch(request);
+        assert!(response.error.is_none());
+        let result = response.result.expect("tools/call result");
+        assert_eq!(result["isError"], false);
+        assert_eq!(result["content"][0]["type"], "text");
+        assert!(result["content"][0]["text"]
+            .as_str()
+            .unwrap()
+            .starts_with("called echo"));
+    }
+
+    #[test]
+    fn dispatch_tools_call_surfaces_handler_error() {
+        let server = McpServer {
+            spec: McpServerSpec {
+                server_name: "test".to_string(),
+                server_version: "0.0.0".to_string(),
+                tools: Vec::new(),
+                tool_handler: Box::new(|_, _| Err("boom".to_string())),
+            },
+            stdin: BufReader::new(stdin()),
+            stdout: stdout(),
+        };
+        let request = JsonRpcRequest::<JsonValue> {
+            jsonrpc: "2.0".to_string(),
+            id: JsonRpcId::Number(4),
+            method: "tools/call".to_string(),
+            params: Some(json!({"name": "broken"})),
+        };
+        let response = server.dispatch(request);
+        let result = response.result.expect("tools/call result");
+        assert_eq!(result["isError"], true);
+        assert_eq!(result["content"][0]["text"], "boom");
+    }
+
+    #[test]
+    fn dispatch_unknown_method_returns_method_not_found() {
+        let server = McpServer {
+            spec: McpServerSpec {
+                server_name: "test".to_string(),
+                server_version: "0.0.0".to_string(),
+                tools: Vec::new(),
+                tool_handler: Box::new(|_, _| Ok(String::new())),
+            },
+            stdin: BufReader::new(stdin()),
+            stdout: stdout(),
+        };
+        let request = JsonRpcRequest::<JsonValue> {
+            jsonrpc: "2.0".to_string(),
+            id: JsonRpcId::Number(5),
+            method: "nonsense".to_string(),
+            params: None,
+        };
+        let response = server.dispatch(request);
+        let error = response.error.expect("error payload");
+        assert_eq!(error.code, -32601);
+    }
+}

rust/crates/runtime/src/prompt.rs

@@ -4,6 +4,7 @@ use std::path::{Path, PathBuf};
 use std::process::Command;
 
 use crate::config::{ConfigError, ConfigLoader, RuntimeConfig};
+use crate::git_context::GitContext;
 
 /// Errors raised while assembling the final system prompt.
 #[derive(Debug)]
@@ -56,6 +57,7 @@ pub struct ProjectContext {
     pub current_date: String,
     pub git_status: Option<String>,
     pub git_diff: Option<String>,
+    pub git_context: Option<GitContext>,
     pub instruction_files: Vec<ContextFile>,
 }
 
@@ -71,6 +73,7 @@ impl ProjectContext {
             current_date: current_date.into(),
             git_status: None,
             git_diff: None,
+            git_context: None,
             instruction_files,
         })
     }
@@ -82,6 +85,7 @@ impl ProjectContext {
         let mut context = Self::discover(cwd, current_date)?;
         context.git_status = read_git_status(&context.cwd);
         context.git_diff = read_git_diff(&context.cwd);
+        context.git_context = GitContext::detect(&context.cwd);
         Ok(context)
     }
 }
@@ -249,6 +253,31 @@ fn read_git_status(cwd: &Path) -> Option<String> {
     }
 }
 
+fn read_git_recent_commits(cwd: &Path) -> Option<String> {
+    let output = Command::new("git")
+        .args([
+            "--no-optional-locks",
+            "log",
+            "--oneline",
+            "--no-decorate",
+            "-n",
+            "5",
+        ])
+        .current_dir(cwd)
+        .output()
+        .ok()?;
+    if !output.status.success() {
+        return None;
+    }
+    let stdout = String::from_utf8(output.stdout).ok()?;
+    let trimmed = stdout.trim();
+    if trimmed.is_empty() {
+        None
+    } else {
+        Some(trimmed.to_string())
+    }
+}
+
 fn read_git_diff(cwd: &Path) -> Option<String> {
     let mut sections = Vec::new();
 
@@ -299,11 +328,27 @@ fn render_project_context(project_context: &ProjectContext) -> String {
         lines.push("Git status snapshot:".to_string());
         lines.push(status.clone());
     }
+    if let Some(ref gc) = project_context.git_context {
+        if !gc.recent_commits.is_empty() {
+            lines.push(String::new());
+            lines.push("Recent commits (last 5):".to_string());
+            for c in &gc.recent_commits {
+                lines.push(format!("  {} {}", c.hash, c.subject));
+            }
+        }
+    }
     if let Some(diff) = &project_context.git_diff {
         lines.push(String::new());
         lines.push("Git diff snapshot:".to_string());
         lines.push(diff.clone());
     }
+    if let Some(git_context) = &project_context.git_context {
+        let rendered = git_context.render();
+        if !rendered.is_empty() {
+            lines.push(String::new());
+            lines.push(rendered);
+        }
+    }
     lines.join("\n")
 }
 
@@ -639,6 +684,80 @@ mod tests {
         fs::remove_dir_all(root).expect("cleanup temp dir");
     }
 
+    #[test]
+    fn discover_with_git_includes_recent_commits_and_renders_them() {
+        // given: a git repo with three commits and a current branch
+        let _guard = env_lock();
+        ensure_valid_cwd();
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("root dir");
+        std::process::Command::new("git")
+            .args(["init", "--quiet", "-b", "main"])
+            .current_dir(&root)
+            .status()
+            .expect("git init should run");
+        std::process::Command::new("git")
+            .args(["config", "user.email", "tests@example.com"])
+            .current_dir(&root)
+            .status()
+            .expect("git config email should run");
+        std::process::Command::new("git")
+            .args(["config", "user.name", "Runtime Prompt Tests"])
+            .current_dir(&root)
+            .status()
+            .expect("git config name should run");
+        for (file, message) in [
+            ("a.txt", "first commit"),
+            ("b.txt", "second commit"),
+            ("c.txt", "third commit"),
+        ] {
+            fs::write(root.join(file), "x\n").expect("write commit file");
+            std::process::Command::new("git")
+                .args(["add", file])
+                .current_dir(&root)
+                .status()
+                .expect("git add should run");
+            std::process::Command::new("git")
+                .args(["commit", "-m", message, "--quiet"])
+                .current_dir(&root)
+                .status()
+                .expect("git commit should run");
+        }
+        fs::write(root.join("d.txt"), "staged\n").expect("write staged file");
+        std::process::Command::new("git")
+            .args(["add", "d.txt"])
+            .current_dir(&root)
+            .status()
+            .expect("git add staged should run");
+
+        // when: discovering project context with git auto-include
+        let context =
+            ProjectContext::discover_with_git(&root, "2026-03-31").expect("context should load");
+        let rendered = SystemPromptBuilder::new()
+            .with_os("linux", "6.8")
+            .with_project_context(context.clone())
+            .render();
+
+        // then: branch, recent commits and staged files are present in context
+        let gc = context.git_context.as_ref().expect("git context should be present");
+        let commits: String = gc.recent_commits.iter().map(|c| c.subject.clone()).collect::<Vec<_>>().join("\n");
+        assert!(commits.contains("first commit"));
+        assert!(commits.contains("second commit"));
+        assert!(commits.contains("third commit"));
+        assert_eq!(gc.recent_commits.len(), 3);
+
+        let status = context.git_status.as_deref().expect("status snapshot");
+        assert!(status.contains("## main"));
+        assert!(status.contains("A  d.txt"));
+
+        assert!(rendered.contains("Recent commits (last 5):"));
+        assert!(rendered.contains("first commit"));
+        assert!(rendered.contains("Git status snapshot:"));
+        assert!(rendered.contains("## main"));
+
+        fs::remove_dir_all(root).expect("cleanup temp dir");
+    }
+
     #[test]
     fn discover_with_git_includes_diff_snapshot_for_tracked_changes() {
         let _guard = env_lock();

rust/crates/runtime/src/session.rs

@@ -65,12 +65,26 @@ pub struct SessionFork {
     pub branch_name: Option<String>,
 }
 
+/// A single user prompt recorded with a timestamp for history tracking.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct SessionPromptEntry {
+    pub timestamp_ms: u64,
+    pub text: String,
+}
+
 #[derive(Debug, Clone, PartialEq, Eq)]
 struct SessionPersistence {
     path: PathBuf,
 }
 
 /// Persisted conversational state for the runtime and CLI session manager.
+///
+/// `workspace_root` binds the session to the worktree it was created in. The
+/// global session store under `~/.local/share/opencode` is shared across every
+/// `opencode serve` instance, so without an explicit workspace root parallel
+/// lanes can race and report success while writes land in the wrong CWD. See
+/// ROADMAP.md item 41 (Phantom completions root cause) for the full
+/// background.
 #[derive(Debug, Clone)]
 pub struct Session {
     pub version: u32,
@@ -80,6 +94,8 @@ pub struct Session {
     pub messages: Vec<ConversationMessage>,
     pub compaction: Option<SessionCompaction>,
     pub fork: Option<SessionFork>,
+    pub workspace_root: Option<PathBuf>,
+    pub prompt_history: Vec<SessionPromptEntry>,
     persistence: Option<SessionPersistence>,
 }
 
@@ -92,6 +108,8 @@ impl PartialEq for Session {
             && self.messages == other.messages
             && self.compaction == other.compaction
             && self.fork == other.fork
+            && self.workspace_root == other.workspace_root
+            && self.prompt_history == other.prompt_history
     }
 }
 
@@ -141,6 +159,8 @@ impl Session {
             messages: Vec::new(),
             compaction: None,
             fork: None,
+            workspace_root: None,
+            prompt_history: Vec::new(),
             persistence: None,
         }
     }
@@ -151,6 +171,22 @@ impl Session {
         self
     }
 
+    /// Bind this session to the workspace root it was created in.
+    ///
+    /// This is the per-worktree counterpart to the global session store and
+    /// lets downstream tooling reject writes that drift to the wrong CWD when
+    /// multiple `opencode serve` instances share `~/.local/share/opencode`.
+    #[must_use]
+    pub fn with_workspace_root(mut self, workspace_root: impl Into<PathBuf>) -> Self {
+        self.workspace_root = Some(workspace_root.into());
+        self
+    }
+
+    #[must_use]
+    pub fn workspace_root(&self) -> Option<&Path> {
+        self.workspace_root.as_deref()
+    }
+
     #[must_use]
     pub fn persistence_path(&self) -> Option<&Path> {
         self.persistence.as_ref().map(|value| value.path.as_path())
@@ -225,6 +261,8 @@ impl Session {
                 parent_session_id: self.session_id.clone(),
                 branch_name: normalize_optional_string(branch_name),
             }),
+            workspace_root: self.workspace_root.clone(),
+            prompt_history: self.prompt_history.clone(),
             persistence: None,
         }
     }
@@ -262,6 +300,23 @@ impl Session {
         if let Some(fork) = &self.fork {
             object.insert("fork".to_string(), fork.to_json());
         }
+        if let Some(workspace_root) = &self.workspace_root {
+            object.insert(
+                "workspace_root".to_string(),
+                JsonValue::String(workspace_root_to_string(workspace_root)?),
+            );
+        }
+        if !self.prompt_history.is_empty() {
+            object.insert(
+                "prompt_history".to_string(),
+                JsonValue::Array(
+                    self.prompt_history
+                        .iter()
+                        .map(SessionPromptEntry::to_jsonl_record)
+                        .collect(),
+                ),
+            );
+        }
         Ok(JsonValue::Object(object))
     }
 
@@ -302,6 +357,20 @@ impl Session {
             .map(SessionCompaction::from_json)
             .transpose()?;
         let fork = object.get("fork").map(SessionFork::from_json).transpose()?;
+        let workspace_root = object
+            .get("workspace_root")
+            .and_then(JsonValue::as_str)
+            .map(PathBuf::from);
+        let prompt_history = object
+            .get("prompt_history")
+            .and_then(JsonValue::as_array)
+            .map(|entries| {
+                entries
+                    .iter()
+                    .filter_map(SessionPromptEntry::from_json_opt)
+                    .collect()
+            })
+            .unwrap_or_default();
         Ok(Self {
             version,
             session_id,
@@ -310,6 +379,8 @@ impl Session {
             messages,
             compaction,
             fork,
+            workspace_root,
+            prompt_history,
             persistence: None,
         })
     }
@@ -322,6 +393,8 @@ impl Session {
         let mut messages = Vec::new();
         let mut compaction = None;
         let mut fork = None;
+        let mut workspace_root = None;
+        let mut prompt_history = Vec::new();
 
         for (line_number, raw_line) in contents.lines().enumerate() {
             let line = raw_line.trim();
@@ -356,6 +429,10 @@ impl Session {
                     created_at_ms = Some(required_u64(object, "created_at_ms")?);
                     updated_at_ms = Some(required_u64(object, "updated_at_ms")?);
                     fork = object.get("fork").map(SessionFork::from_json).transpose()?;
+                    workspace_root = object
+                        .get("workspace_root")
+                        .and_then(JsonValue::as_str)
+                        .map(PathBuf::from);
                 }
                 "message" => {
                     let message_value = object.get("message").ok_or_else(|| {
@@ -371,6 +448,13 @@ impl Session {
                         object.clone(),
                     ))?);
                 }
+                "prompt_history" => {
+                    if let Some(entry) =
+                        SessionPromptEntry::from_json_opt(&JsonValue::Object(object.clone()))
+                    {
+                        prompt_history.push(entry);
+                    }
+                }
                 other => {
                     return Err(SessionError::Format(format!(
                         "unsupported JSONL record type at line {}: {other}",
@@ -389,15 +473,37 @@ impl Session {
             messages,
             compaction,
             fork,
+            workspace_root,
+            prompt_history,
             persistence: None,
         })
     }
 
+    /// Record a user prompt with the current wall-clock timestamp.
+    ///
+    /// The entry is appended to the in-memory history and, when a persistence
+    /// path is configured, incrementally written to the JSONL session file.
+    pub fn push_prompt_entry(&mut self, text: impl Into<String>) -> Result<(), SessionError> {
+        let timestamp_ms = current_time_millis();
+        let entry = SessionPromptEntry {
+            timestamp_ms,
+            text: text.into(),
+        };
+        self.prompt_history.push(entry);
+        let entry_ref = self.prompt_history.last().expect("entry was just pushed");
+        self.append_persisted_prompt_entry(entry_ref)
+    }
+
     fn render_jsonl_snapshot(&self) -> Result<String, SessionError> {
         let mut lines = vec![self.meta_record()?.render()];
         if let Some(compaction) = &self.compaction {
             lines.push(compaction.to_jsonl_record()?.render());
         }
+        lines.extend(
+            self.prompt_history
+                .iter()
+                .map(|entry| entry.to_jsonl_record().render()),
+        );
         lines.extend(
             self.messages
                 .iter()
@@ -424,6 +530,25 @@ impl Session {
         Ok(())
     }
 
+    fn append_persisted_prompt_entry(
+        &self,
+        entry: &SessionPromptEntry,
+    ) -> Result<(), SessionError> {
+        let Some(path) = self.persistence_path() else {
+            return Ok(());
+        };
+
+        let needs_bootstrap = !path.exists() || fs::metadata(path)?.len() == 0;
+        if needs_bootstrap {
+            self.save_to_path(path)?;
+            return Ok(());
+        }
+
+        let mut file = OpenOptions::new().append(true).open(path)?;
+        writeln!(file, "{}", entry.to_jsonl_record().render())?;
+        Ok(())
+    }
+
     fn meta_record(&self) -> Result<JsonValue, SessionError> {
         let mut object = BTreeMap::new();
         object.insert(
@@ -449,6 +574,12 @@ impl Session {
         if let Some(fork) = &self.fork {
             object.insert("fork".to_string(), fork.to_json());
         }
+        if let Some(workspace_root) = &self.workspace_root {
+            object.insert(
+                "workspace_root".to_string(),
+                JsonValue::String(workspace_root_to_string(workspace_root)?),
+            );
+        }
         Ok(JsonValue::Object(object))
     }
 
@@ -734,6 +865,33 @@ impl SessionFork {
     }
 }
 
+impl SessionPromptEntry {
+    #[must_use]
+    pub fn to_jsonl_record(&self) -> JsonValue {
+        let mut object = BTreeMap::new();
+        object.insert(
+            "type".to_string(),
+            JsonValue::String("prompt_history".to_string()),
+        );
+        object.insert(
+            "timestamp_ms".to_string(),
+            JsonValue::Number(i64::try_from(self.timestamp_ms).unwrap_or(i64::MAX)),
+        );
+        object.insert("text".to_string(), JsonValue::String(self.text.clone()));
+        JsonValue::Object(object)
+    }
+
+    fn from_json_opt(value: &JsonValue) -> Option<Self> {
+        let object = value.as_object()?;
+        let timestamp_ms = object
+            .get("timestamp_ms")
+            .and_then(JsonValue::as_i64)
+            .and_then(|value| u64::try_from(value).ok())?;
+        let text = object.get("text").and_then(JsonValue::as_str)?.to_string();
+        Some(Self { timestamp_ms, text })
+    }
+}
+
 fn message_record(message: &ConversationMessage) -> JsonValue {
     let mut object = BTreeMap::new();
     object.insert("type".to_string(), JsonValue::String("message".to_string()));
@@ -825,6 +983,15 @@ fn i64_from_usize(value: usize, key: &str) -> Result<i64, SessionError> {
         .map_err(|_| SessionError::Format(format!("{key} out of range for JSON number")))
 }
 
+fn workspace_root_to_string(path: &Path) -> Result<String, SessionError> {
+    path.to_str().map(ToOwned::to_owned).ok_or_else(|| {
+        SessionError::Format(format!(
+            "workspace_root is not valid UTF-8: {}",
+            path.display()
+        ))
+    })
+}
+
 fn normalize_optional_string(value: Option<String>) -> Option<String> {
     value.and_then(|value| {
         let trimmed = value.trim();
@@ -1206,6 +1373,29 @@ mod tests {
         assert!(error.to_string().contains("unsupported block type"));
     }
 
+    #[test]
+    fn persists_workspace_root_round_trip_and_forks_inherit_it() {
+        // given
+        let path = temp_session_path("workspace-root");
+        let workspace_root = PathBuf::from("/tmp/b4-phantom-diag");
+        let mut session = Session::new().with_workspace_root(workspace_root.clone());
+        session
+            .push_user_text("write to the right cwd")
+            .expect("user message should append");
+
+        // when
+        session
+            .save_to_path(&path)
+            .expect("workspace-bound session should save");
+        let restored = Session::load_from_path(&path).expect("session should load");
+        let forked = restored.fork(Some("phantom-diag".to_string()));
+        fs::remove_file(&path).expect("temp file should be removable");
+
+        // then
+        assert_eq!(restored.workspace_root(), Some(workspace_root.as_path()));
+        assert_eq!(forked.workspace_root(), Some(workspace_root.as_path()));
+    }
+
     fn temp_session_path(label: &str) -> PathBuf {
         let nanos = SystemTime::now()
             .duration_since(UNIX_EPOCH)
@@ -1244,3 +1434,12 @@ mod tests {
             .collect()
     }
 }
+
+/// Per-worktree session isolation: returns a session directory namespaced
+/// by the workspace fingerprint of the given working directory.
+/// This prevents parallel `opencode serve` instances from colliding.
+pub fn workspace_sessions_dir(cwd: &std::path::Path) -> Result<std::path::PathBuf, SessionError> {
+    let store = crate::session_control::SessionStore::from_cwd(cwd)
+        .map_err(|e| SessionError::Io(std::io::Error::new(std::io::ErrorKind::Other, e.to_string())))?;
+    Ok(store.sessions_dir().to_path_buf())
+}

rust/crates/runtime/src/session_control.rs

@@ -7,6 +7,252 @@ use std::time::UNIX_EPOCH;
 
 use crate::session::{Session, SessionError};
 
+/// Per-worktree session store that namespaces on-disk session files by
+/// workspace fingerprint so that parallel `opencode serve` instances never
+/// collide.
+///
+/// Create via [`SessionStore::from_cwd`] (derives the store path from the
+/// server's working directory) or [`SessionStore::from_data_dir`] (honours an
+/// explicit `--data-dir` flag).  Both constructors produce a directory layout
+/// of `<data_dir>/sessions/<workspace_hash>/` where `<workspace_hash>` is a
+/// stable hex digest of the canonical workspace root.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct SessionStore {
+    /// Resolved root of the session namespace, e.g.
+    /// `/home/user/project/.claw/sessions/a1b2c3d4e5f60718/`.
+    sessions_root: PathBuf,
+    /// The canonical workspace path that was fingerprinted.
+    workspace_root: PathBuf,
+}
+
+impl SessionStore {
+    /// Build a store from the server's current working directory.
+    ///
+    /// The on-disk layout becomes `<cwd>/.claw/sessions/<workspace_hash>/`.
+    pub fn from_cwd(cwd: impl AsRef<Path>) -> Result<Self, SessionControlError> {
+        let cwd = cwd.as_ref();
+        let sessions_root = cwd
+            .join(".claw")
+            .join("sessions")
+            .join(workspace_fingerprint(cwd));
+        fs::create_dir_all(&sessions_root)?;
+        Ok(Self {
+            sessions_root,
+            workspace_root: cwd.to_path_buf(),
+        })
+    }
+
+    /// Build a store from an explicit `--data-dir` flag.
+    ///
+    /// The on-disk layout becomes `<data_dir>/sessions/<workspace_hash>/`
+    /// where `<workspace_hash>` is derived from `workspace_root`.
+    pub fn from_data_dir(
+        data_dir: impl AsRef<Path>,
+        workspace_root: impl AsRef<Path>,
+    ) -> Result<Self, SessionControlError> {
+        let workspace_root = workspace_root.as_ref();
+        let sessions_root = data_dir
+            .as_ref()
+            .join("sessions")
+            .join(workspace_fingerprint(workspace_root));
+        fs::create_dir_all(&sessions_root)?;
+        Ok(Self {
+            sessions_root,
+            workspace_root: workspace_root.to_path_buf(),
+        })
+    }
+
+    /// The fully resolved sessions directory for this namespace.
+    #[must_use]
+    pub fn sessions_dir(&self) -> &Path {
+        &self.sessions_root
+    }
+
+    /// The workspace root this store is bound to.
+    #[must_use]
+    pub fn workspace_root(&self) -> &Path {
+        &self.workspace_root
+    }
+
+    pub fn create_handle(&self, session_id: &str) -> SessionHandle {
+        let id = session_id.to_string();
+        let path = self
+            .sessions_root
+            .join(format!("{id}.{PRIMARY_SESSION_EXTENSION}"));
+        SessionHandle { id, path }
+    }
+
+    pub fn resolve_reference(&self, reference: &str) -> Result<SessionHandle, SessionControlError> {
+        if is_session_reference_alias(reference) {
+            let latest = self.latest_session()?;
+            return Ok(SessionHandle {
+                id: latest.id,
+                path: latest.path,
+            });
+        }
+
+        let direct = PathBuf::from(reference);
+        let candidate = if direct.is_absolute() {
+            direct.clone()
+        } else {
+            self.workspace_root.join(&direct)
+        };
+        let looks_like_path = direct.extension().is_some() || direct.components().count() > 1;
+        let path = if candidate.exists() {
+            candidate
+        } else if looks_like_path {
+            return Err(SessionControlError::Format(
+                format_missing_session_reference(reference),
+            ));
+        } else {
+            self.resolve_managed_path(reference)?
+        };
+
+        Ok(SessionHandle {
+            id: session_id_from_path(&path).unwrap_or_else(|| reference.to_string()),
+            path,
+        })
+    }
+
+    pub fn resolve_managed_path(&self, session_id: &str) -> Result<PathBuf, SessionControlError> {
+        for extension in [PRIMARY_SESSION_EXTENSION, LEGACY_SESSION_EXTENSION] {
+            let path = self.sessions_root.join(format!("{session_id}.{extension}"));
+            if path.exists() {
+                return Ok(path);
+            }
+        }
+        Err(SessionControlError::Format(
+            format_missing_session_reference(session_id),
+        ))
+    }
+
+    pub fn list_sessions(&self) -> Result<Vec<ManagedSessionSummary>, SessionControlError> {
+        let mut sessions = Vec::new();
+        let read_result = fs::read_dir(&self.sessions_root);
+        let entries = match read_result {
+            Ok(entries) => entries,
+            Err(err) if err.kind() == std::io::ErrorKind::NotFound => return Ok(sessions),
+            Err(err) => return Err(err.into()),
+        };
+        for entry in entries {
+            let entry = entry?;
+            let path = entry.path();
+            if !is_managed_session_file(&path) {
+                continue;
+            }
+            let metadata = entry.metadata()?;
+            let modified_epoch_millis = metadata
+                .modified()
+                .ok()
+                .and_then(|time| time.duration_since(UNIX_EPOCH).ok())
+                .map(|duration| duration.as_millis())
+                .unwrap_or_default();
+            let (id, message_count, parent_session_id, branch_name) =
+                match Session::load_from_path(&path) {
+                    Ok(session) => {
+                        let parent_session_id = session
+                            .fork
+                            .as_ref()
+                            .map(|fork| fork.parent_session_id.clone());
+                        let branch_name = session
+                            .fork
+                            .as_ref()
+                            .and_then(|fork| fork.branch_name.clone());
+                        (
+                            session.session_id,
+                            session.messages.len(),
+                            parent_session_id,
+                            branch_name,
+                        )
+                    }
+                    Err(_) => (
+                        path.file_stem()
+                            .and_then(|value| value.to_str())
+                            .unwrap_or("unknown")
+                            .to_string(),
+                        0,
+                        None,
+                        None,
+                    ),
+                };
+            sessions.push(ManagedSessionSummary {
+                id,
+                path,
+                modified_epoch_millis,
+                message_count,
+                parent_session_id,
+                branch_name,
+            });
+        }
+        sessions.sort_by(|left, right| {
+            right
+                .modified_epoch_millis
+                .cmp(&left.modified_epoch_millis)
+                .then_with(|| right.id.cmp(&left.id))
+        });
+        Ok(sessions)
+    }
+
+    pub fn latest_session(&self) -> Result<ManagedSessionSummary, SessionControlError> {
+        self.list_sessions()?
+            .into_iter()
+            .next()
+            .ok_or_else(|| SessionControlError::Format(format_no_managed_sessions()))
+    }
+
+    pub fn load_session(
+        &self,
+        reference: &str,
+    ) -> Result<LoadedManagedSession, SessionControlError> {
+        let handle = self.resolve_reference(reference)?;
+        let session = Session::load_from_path(&handle.path)?;
+        Ok(LoadedManagedSession {
+            handle: SessionHandle {
+                id: session.session_id.clone(),
+                path: handle.path,
+            },
+            session,
+        })
+    }
+
+    pub fn fork_session(
+        &self,
+        session: &Session,
+        branch_name: Option<String>,
+    ) -> Result<ForkedManagedSession, SessionControlError> {
+        let parent_session_id = session.session_id.clone();
+        let forked = session.fork(branch_name);
+        let handle = self.create_handle(&forked.session_id);
+        let branch_name = forked
+            .fork
+            .as_ref()
+            .and_then(|fork| fork.branch_name.clone());
+        let forked = forked.with_persistence_path(handle.path.clone());
+        forked.save_to_path(&handle.path)?;
+        Ok(ForkedManagedSession {
+            parent_session_id,
+            handle,
+            session: forked,
+            branch_name,
+        })
+    }
+}
+
+/// Stable hex fingerprint of a workspace path.
+///
+/// Uses FNV-1a (64-bit) to produce a 16-char hex string that partitions the
+/// on-disk session directory per workspace root.
+#[must_use]
+pub fn workspace_fingerprint(workspace_root: &Path) -> String {
+    let input = workspace_root.to_string_lossy();
+    let mut hash = 0xcbf2_9ce4_8422_2325_u64;
+    for byte in input.as_bytes() {
+        hash ^= u64::from(*byte);
+        hash = hash.wrapping_mul(0x0100_0000_01b3);
+    }
+    format!("{hash:016x}")
+}
+
 pub const PRIMARY_SESSION_EXTENSION: &str = "jsonl";
 pub const LEGACY_SESSION_EXTENSION: &str = "json";
 pub const LATEST_SESSION_REFERENCE: &str = "latest";
@@ -333,7 +579,7 @@ mod tests {
     use super::{
         create_managed_session_handle_for, fork_managed_session_for, is_session_reference_alias,
         list_managed_sessions_for, load_managed_session_for, resolve_session_reference_for,
-        ManagedSessionSummary, LATEST_SESSION_REFERENCE,
+        workspace_fingerprint, ManagedSessionSummary, SessionStore, LATEST_SESSION_REFERENCE,
     };
     use crate::session::Session;
     use std::fs;
@@ -456,4 +702,172 @@ mod tests {
         );
         fs::remove_dir_all(root).expect("temp dir should clean up");
     }
+
+    // ------------------------------------------------------------------
+    // Per-worktree session isolation (SessionStore) tests
+    // ------------------------------------------------------------------
+
+    fn persist_session_via_store(store: &SessionStore, text: &str) -> Session {
+        let mut session = Session::new();
+        session
+            .push_user_text(text)
+            .expect("session message should save");
+        let handle = store.create_handle(&session.session_id);
+        let session = session.with_persistence_path(handle.path.clone());
+        session
+            .save_to_path(&handle.path)
+            .expect("session should persist");
+        session
+    }
+
+    #[test]
+    fn workspace_fingerprint_is_deterministic_and_differs_per_path() {
+        // given
+        let path_a = Path::new("/tmp/worktree-alpha");
+        let path_b = Path::new("/tmp/worktree-beta");
+
+        // when
+        let fp_a1 = workspace_fingerprint(path_a);
+        let fp_a2 = workspace_fingerprint(path_a);
+        let fp_b = workspace_fingerprint(path_b);
+
+        // then
+        assert_eq!(fp_a1, fp_a2, "same path must produce the same fingerprint");
+        assert_ne!(
+            fp_a1, fp_b,
+            "different paths must produce different fingerprints"
+        );
+        assert_eq!(fp_a1.len(), 16, "fingerprint must be a 16-char hex string");
+    }
+
+    #[test]
+    fn session_store_from_cwd_isolates_sessions_by_workspace() {
+        // given
+        let base = temp_dir();
+        let workspace_a = base.join("repo-alpha");
+        let workspace_b = base.join("repo-beta");
+        fs::create_dir_all(&workspace_a).expect("workspace a should exist");
+        fs::create_dir_all(&workspace_b).expect("workspace b should exist");
+
+        let store_a = SessionStore::from_cwd(&workspace_a).expect("store a should build");
+        let store_b = SessionStore::from_cwd(&workspace_b).expect("store b should build");
+
+        // when
+        let session_a = persist_session_via_store(&store_a, "alpha work");
+        let _session_b = persist_session_via_store(&store_b, "beta work");
+
+        // then — each store only sees its own sessions
+        let list_a = store_a.list_sessions().expect("list a");
+        let list_b = store_b.list_sessions().expect("list b");
+        assert_eq!(list_a.len(), 1, "store a should see exactly one session");
+        assert_eq!(list_b.len(), 1, "store b should see exactly one session");
+        assert_eq!(list_a[0].id, session_a.session_id);
+        assert_ne!(
+            store_a.sessions_dir(),
+            store_b.sessions_dir(),
+            "session directories must differ across workspaces"
+        );
+        fs::remove_dir_all(base).expect("temp dir should clean up");
+    }
+
+    #[test]
+    fn session_store_from_data_dir_namespaces_by_workspace() {
+        // given
+        let base = temp_dir();
+        let data_dir = base.join("global-data");
+        let workspace_a = PathBuf::from("/tmp/project-one");
+        let workspace_b = PathBuf::from("/tmp/project-two");
+        fs::create_dir_all(&data_dir).expect("data dir should exist");
+
+        let store_a =
+            SessionStore::from_data_dir(&data_dir, &workspace_a).expect("store a should build");
+        let store_b =
+            SessionStore::from_data_dir(&data_dir, &workspace_b).expect("store b should build");
+
+        // when
+        persist_session_via_store(&store_a, "work in project-one");
+        persist_session_via_store(&store_b, "work in project-two");
+
+        // then
+        assert_ne!(
+            store_a.sessions_dir(),
+            store_b.sessions_dir(),
+            "data-dir stores must namespace by workspace"
+        );
+        assert_eq!(store_a.list_sessions().expect("list a").len(), 1);
+        assert_eq!(store_b.list_sessions().expect("list b").len(), 1);
+        assert_eq!(store_a.workspace_root(), workspace_a.as_path());
+        assert_eq!(store_b.workspace_root(), workspace_b.as_path());
+        fs::remove_dir_all(base).expect("temp dir should clean up");
+    }
+
+    #[test]
+    fn session_store_create_and_load_round_trip() {
+        // given
+        let base = temp_dir();
+        fs::create_dir_all(&base).expect("base dir should exist");
+        let store = SessionStore::from_cwd(&base).expect("store should build");
+        let session = persist_session_via_store(&store, "round-trip message");
+
+        // when
+        let loaded = store
+            .load_session(&session.session_id)
+            .expect("session should load via store");
+
+        // then
+        assert_eq!(loaded.handle.id, session.session_id);
+        assert_eq!(loaded.session.messages.len(), 1);
+        fs::remove_dir_all(base).expect("temp dir should clean up");
+    }
+
+    #[test]
+    fn session_store_latest_and_resolve_reference() {
+        // given
+        let base = temp_dir();
+        fs::create_dir_all(&base).expect("base dir should exist");
+        let store = SessionStore::from_cwd(&base).expect("store should build");
+        let _older = persist_session_via_store(&store, "older");
+        wait_for_next_millisecond();
+        let newer = persist_session_via_store(&store, "newer");
+
+        // when
+        let latest = store.latest_session().expect("latest should resolve");
+        let handle = store
+            .resolve_reference("latest")
+            .expect("latest alias should resolve");
+
+        // then
+        assert_eq!(latest.id, newer.session_id);
+        assert_eq!(handle.id, newer.session_id);
+        fs::remove_dir_all(base).expect("temp dir should clean up");
+    }
+
+    #[test]
+    fn session_store_fork_stays_in_same_namespace() {
+        // given
+        let base = temp_dir();
+        fs::create_dir_all(&base).expect("base dir should exist");
+        let store = SessionStore::from_cwd(&base).expect("store should build");
+        let source = persist_session_via_store(&store, "parent work");
+
+        // when
+        let forked = store
+            .fork_session(&source, Some("bugfix".to_string()))
+            .expect("fork should succeed");
+        let sessions = store.list_sessions().expect("list sessions");
+
+        // then
+        assert_eq!(
+            sessions.len(),
+            2,
+            "forked session must land in the same namespace"
+        );
+        assert_eq!(forked.parent_session_id, source.session_id);
+        assert_eq!(forked.branch_name.as_deref(), Some("bugfix"));
+        assert!(
+            forked.handle.path.starts_with(store.sessions_dir()),
+            "forked session path must be inside the store namespace"
+        );
+        fs::remove_dir_all(base).expect("temp dir should clean up");
+    }
 }

rust/crates/runtime/src/stale_base.rs

@@ -0,0 +1,429 @@
+#![allow(clippy::must_use_candidate)]
+use std::path::Path;
+use std::process::Command;
+
+/// Outcome of comparing the worktree HEAD against the expected base commit.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum BaseCommitState {
+    /// HEAD matches the expected base commit.
+    Matches,
+    /// HEAD has diverged from the expected base.
+    Diverged { expected: String, actual: String },
+    /// No expected base was supplied (neither flag nor file).
+    NoExpectedBase,
+    /// The working directory is not inside a git repository.
+    NotAGitRepo,
+}
+
+/// Where the expected base commit originated from.
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub enum BaseCommitSource {
+    Flag(String),
+    File(String),
+}
+
+/// Read the `.claw-base` file from the given directory and return the trimmed
+/// commit hash, or `None` when the file is absent or empty.
+pub fn read_claw_base_file(cwd: &Path) -> Option<String> {
+    let path = cwd.join(".claw-base");
+    let content = std::fs::read_to_string(path).ok()?;
+    let trimmed = content.trim();
+    if trimmed.is_empty() {
+        None
+    } else {
+        Some(trimmed.to_string())
+    }
+}
+
+/// Resolve the expected base commit: prefer the `--base-commit` flag value,
+/// fall back to reading `.claw-base` from `cwd`.
+pub fn resolve_expected_base(flag_value: Option<&str>, cwd: &Path) -> Option<BaseCommitSource> {
+    if let Some(value) = flag_value {
+        let trimmed = value.trim();
+        if !trimmed.is_empty() {
+            return Some(BaseCommitSource::Flag(trimmed.to_string()));
+        }
+    }
+    read_claw_base_file(cwd).map(BaseCommitSource::File)
+}
+
+/// Verify that the worktree HEAD matches `expected_base`.
+///
+/// Returns [`BaseCommitState::NoExpectedBase`] when no expected commit is
+/// provided (the check is effectively a no-op in that case).
+pub fn check_base_commit(cwd: &Path, expected_base: Option<&BaseCommitSource>) -> BaseCommitState {
+    let Some(source) = expected_base else {
+        return BaseCommitState::NoExpectedBase;
+    };
+    let expected_raw = match source {
+        BaseCommitSource::Flag(value) | BaseCommitSource::File(value) => value.as_str(),
+    };
+
+    let Some(head_sha) = resolve_head_sha(cwd) else {
+        return BaseCommitState::NotAGitRepo;
+    };
+
+    let Some(expected_sha) = resolve_rev(cwd, expected_raw) else {
+        // If the expected ref cannot be resolved, compare raw strings as a
+        // best-effort fallback (e.g. partial SHA provided by the caller).
+        return if head_sha.starts_with(expected_raw) || expected_raw.starts_with(&head_sha) {
+            BaseCommitState::Matches
+        } else {
+            BaseCommitState::Diverged {
+                expected: expected_raw.to_string(),
+                actual: head_sha,
+            }
+        };
+    };
+
+    if head_sha == expected_sha {
+        BaseCommitState::Matches
+    } else {
+        BaseCommitState::Diverged {
+            expected: expected_sha,
+            actual: head_sha,
+        }
+    }
+}
+
+/// Format a human-readable warning when the base commit has diverged.
+///
+/// Returns `None` for non-warning states (`Matches`, `NoExpectedBase`).
+pub fn format_stale_base_warning(state: &BaseCommitState) -> Option<String> {
+    match state {
+        BaseCommitState::Diverged { expected, actual } => Some(format!(
+            "warning: worktree HEAD ({actual}) does not match expected base commit ({expected}). \
+             Session may run against a stale codebase."
+        )),
+        BaseCommitState::NotAGitRepo => {
+            Some("warning: stale-base check skipped — not inside a git repository.".to_string())
+        }
+        BaseCommitState::Matches | BaseCommitState::NoExpectedBase => None,
+    }
+}
+
+fn resolve_head_sha(cwd: &Path) -> Option<String> {
+    resolve_rev(cwd, "HEAD")
+}
+
+fn resolve_rev(cwd: &Path, rev: &str) -> Option<String> {
+    let output = Command::new("git")
+        .args(["rev-parse", rev])
+        .current_dir(cwd)
+        .output()
+        .ok()?;
+    if !output.status.success() {
+        return None;
+    }
+    let sha = String::from_utf8(output.stdout).ok()?;
+    let trimmed = sha.trim();
+    if trimmed.is_empty() {
+        None
+    } else {
+        Some(trimmed.to_string())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::fs;
+    use std::process::Command;
+    use std::time::{SystemTime, UNIX_EPOCH};
+
+    fn temp_dir() -> std::path::PathBuf {
+        let nanos = SystemTime::now()
+            .duration_since(UNIX_EPOCH)
+            .expect("time should be after epoch")
+            .as_nanos();
+        std::env::temp_dir().join(format!("runtime-stale-base-{nanos}"))
+    }
+
+    fn init_repo(path: &std::path::Path) {
+        fs::create_dir_all(path).expect("create repo dir");
+        run(path, &["init", "--quiet", "-b", "main"]);
+        run(path, &["config", "user.email", "tests@example.com"]);
+        run(path, &["config", "user.name", "Stale Base Tests"]);
+        fs::write(path.join("init.txt"), "initial\n").expect("write init file");
+        run(path, &["add", "."]);
+        run(path, &["commit", "-m", "initial commit", "--quiet"]);
+    }
+
+    fn run(cwd: &std::path::Path, args: &[&str]) {
+        let status = Command::new("git")
+            .args(args)
+            .current_dir(cwd)
+            .status()
+            .unwrap_or_else(|e| panic!("git {} failed to execute: {e}", args.join(" ")));
+        assert!(
+            status.success(),
+            "git {} exited with {status}",
+            args.join(" ")
+        );
+    }
+
+    fn commit_file(repo: &std::path::Path, name: &str, msg: &str) {
+        fs::write(repo.join(name), format!("{msg}\n")).expect("write file");
+        run(repo, &["add", name]);
+        run(repo, &["commit", "-m", msg, "--quiet"]);
+    }
+
+    fn head_sha(repo: &std::path::Path) -> String {
+        let output = Command::new("git")
+            .args(["rev-parse", "HEAD"])
+            .current_dir(repo)
+            .output()
+            .expect("git rev-parse HEAD");
+        String::from_utf8(output.stdout)
+            .expect("valid utf8")
+            .trim()
+            .to_string()
+    }
+
+    #[test]
+    fn matches_when_head_equals_expected_base() {
+        // given
+        let root = temp_dir();
+        init_repo(&root);
+        let sha = head_sha(&root);
+        let source = BaseCommitSource::Flag(sha);
+
+        // when
+        let state = check_base_commit(&root, Some(&source));
+
+        // then
+        assert_eq!(state, BaseCommitState::Matches);
+        fs::remove_dir_all(&root).expect("cleanup");
+    }
+
+    #[test]
+    fn diverged_when_head_moved_past_expected_base() {
+        // given
+        let root = temp_dir();
+        init_repo(&root);
+        let old_sha = head_sha(&root);
+        commit_file(&root, "extra.txt", "move head forward");
+        let new_sha = head_sha(&root);
+        let source = BaseCommitSource::Flag(old_sha.clone());
+
+        // when
+        let state = check_base_commit(&root, Some(&source));
+
+        // then
+        assert_eq!(
+            state,
+            BaseCommitState::Diverged {
+                expected: old_sha,
+                actual: new_sha,
+            }
+        );
+        fs::remove_dir_all(&root).expect("cleanup");
+    }
+
+    #[test]
+    fn no_expected_base_when_source_is_none() {
+        // given
+        let root = temp_dir();
+        init_repo(&root);
+
+        // when
+        let state = check_base_commit(&root, None);
+
+        // then
+        assert_eq!(state, BaseCommitState::NoExpectedBase);
+        fs::remove_dir_all(&root).expect("cleanup");
+    }
+
+    #[test]
+    fn not_a_git_repo_when_outside_repo() {
+        // given
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("create dir");
+        let source = BaseCommitSource::Flag("abc1234".to_string());
+
+        // when
+        let state = check_base_commit(&root, Some(&source));
+
+        // then
+        assert_eq!(state, BaseCommitState::NotAGitRepo);
+        fs::remove_dir_all(&root).expect("cleanup");
+    }
+
+    #[test]
+    fn reads_claw_base_file() {
+        // given
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("create dir");
+        fs::write(root.join(".claw-base"), "abc1234def5678\n").expect("write .claw-base");
+
+        // when
+        let value = read_claw_base_file(&root);
+
+        // then
+        assert_eq!(value, Some("abc1234def5678".to_string()));
+        fs::remove_dir_all(&root).expect("cleanup");
+    }
+
+    #[test]
+    fn returns_none_for_missing_claw_base_file() {
+        // given
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("create dir");
+
+        // when
+        let value = read_claw_base_file(&root);
+
+        // then
+        assert!(value.is_none());
+        fs::remove_dir_all(&root).expect("cleanup");
+    }
+
+    #[test]
+    fn returns_none_for_empty_claw_base_file() {
+        // given
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("create dir");
+        fs::write(root.join(".claw-base"), "  \n").expect("write empty .claw-base");
+
+        // when
+        let value = read_claw_base_file(&root);
+
+        // then
+        assert!(value.is_none());
+        fs::remove_dir_all(&root).expect("cleanup");
+    }
+
+    #[test]
+    fn resolve_expected_base_prefers_flag_over_file() {
+        // given
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("create dir");
+        fs::write(root.join(".claw-base"), "from_file\n").expect("write .claw-base");
+
+        // when
+        let source = resolve_expected_base(Some("from_flag"), &root);
+
+        // then
+        assert_eq!(
+            source,
+            Some(BaseCommitSource::Flag("from_flag".to_string()))
+        );
+        fs::remove_dir_all(&root).expect("cleanup");
+    }
+
+    #[test]
+    fn resolve_expected_base_falls_back_to_file() {
+        // given
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("create dir");
+        fs::write(root.join(".claw-base"), "from_file\n").expect("write .claw-base");
+
+        // when
+        let source = resolve_expected_base(None, &root);
+
+        // then
+        assert_eq!(
+            source,
+            Some(BaseCommitSource::File("from_file".to_string()))
+        );
+        fs::remove_dir_all(&root).expect("cleanup");
+    }
+
+    #[test]
+    fn resolve_expected_base_returns_none_when_nothing_available() {
+        // given
+        let root = temp_dir();
+        fs::create_dir_all(&root).expect("create dir");
+
+        // when
+        let source = resolve_expected_base(None, &root);
+
+        // then
+        assert!(source.is_none());
+        fs::remove_dir_all(&root).expect("cleanup");
+    }
+
+    #[test]
+    fn format_warning_returns_message_for_diverged() {
+        // given
+        let state = BaseCommitState::Diverged {
+            expected: "abc1234".to_string(),
+            actual: "def5678".to_string(),
+        };
+
+        // when
+        let warning = format_stale_base_warning(&state);
+
+        // then
+        let message = warning.expect("should produce warning");
+        assert!(message.contains("abc1234"));
+        assert!(message.contains("def5678"));
+        assert!(message.contains("stale codebase"));
+    }
+
+    #[test]
+    fn format_warning_returns_none_for_matches() {
+        // given
+        let state = BaseCommitState::Matches;
+
+        // when
+        let warning = format_stale_base_warning(&state);
+
+        // then
+        assert!(warning.is_none());
+    }
+
+    #[test]
+    fn format_warning_returns_none_for_no_expected_base() {
+        // given
+        let state = BaseCommitState::NoExpectedBase;
+
+        // when
+        let warning = format_stale_base_warning(&state);
+
+        // then
+        assert!(warning.is_none());
+    }
+
+    #[test]
+    fn matches_with_claw_base_file_in_real_repo() {
+        // given
+        let root = temp_dir();
+        init_repo(&root);
+        let sha = head_sha(&root);
+        fs::write(root.join(".claw-base"), format!("{sha}\n")).expect("write .claw-base");
+        let source = resolve_expected_base(None, &root);
+
+        // when
+        let state = check_base_commit(&root, source.as_ref());
+
+        // then
+        assert_eq!(state, BaseCommitState::Matches);
+        fs::remove_dir_all(&root).expect("cleanup");
+    }
+
+    #[test]
+    fn diverged_with_claw_base_file_after_new_commit() {
+        // given
+        let root = temp_dir();
+        init_repo(&root);
+        let old_sha = head_sha(&root);
+        fs::write(root.join(".claw-base"), format!("{old_sha}\n")).expect("write .claw-base");
+        commit_file(&root, "new.txt", "advance head");
+        let new_sha = head_sha(&root);
+        let source = resolve_expected_base(None, &root);
+
+        // when
+        let state = check_base_commit(&root, source.as_ref());
+
+        // then
+        assert_eq!(
+            state,
+            BaseCommitState::Diverged {
+                expected: old_sha,
+                actual: new_sha,
+            }
+        );
+        fs::remove_dir_all(&root).expect("cleanup");
+    }
+}

rust/crates/rusty-claude-cli/src/render.rs

@@ -249,13 +249,14 @@ impl TerminalRenderer {
 
     #[must_use]
     pub fn render_markdown(&self, markdown: &str) -> String {
+        let normalized = normalize_nested_fences(markdown);
         let mut output = String::new();
         let mut state = RenderState::default();
         let mut code_language = String::new();
         let mut code_buffer = String::new();
         let mut in_code_block = false;
 
-        for event in Parser::new_ext(markdown, Options::all()) {
+        for event in Parser::new_ext(&normalized, Options::all()) {
             self.render_event(
                 event,
                 &mut state,
@@ -634,8 +635,180 @@ fn apply_code_block_background(line: &str) -> String {
     format!("\u{1b}[48;5;236m{with_background}\u{1b}[0m{trailing_newline}")
 }
 
+/// Pre-process raw markdown so that fenced code blocks whose body contains
+/// fence markers of equal or greater length are wrapped with a longer fence.
+///
+/// LLMs frequently emit triple-backtick code blocks that contain triple-backtick
+/// examples.  CommonMark (and pulldown-cmark) treats the inner marker as the
+/// closing fence, breaking the render.  This function detects the situation and
+/// upgrades the outer fence to use enough backticks (or tildes) that the inner
+/// markers become ordinary content.
+fn normalize_nested_fences(markdown: &str) -> String {
+    // A fence line is either "labeled" (has an info string ⇒ always an opener)
+    // or "bare" (no info string ⇒ could be opener or closer).
+    #[derive(Debug, Clone)]
+    struct FenceLine {
+        char: char,
+        len: usize,
+        has_info: bool,
+        indent: usize,
+    }
+
+    fn parse_fence_line(line: &str) -> Option<FenceLine> {
+        let trimmed = line.trim_end_matches('\n').trim_end_matches('\r');
+        let indent = trimmed.chars().take_while(|c| *c == ' ').count();
+        if indent > 3 {
+            return None;
+        }
+        let rest = &trimmed[indent..];
+        let ch = rest.chars().next()?;
+        if ch != '`' && ch != '~' {
+            return None;
+        }
+        let len = rest.chars().take_while(|c| *c == ch).count();
+        if len < 3 {
+            return None;
+        }
+        let after = &rest[len..];
+        if ch == '`' && after.contains('`') {
+            return None;
+        }
+        let has_info = !after.trim().is_empty();
+        Some(FenceLine {
+            char: ch,
+            len,
+            has_info,
+            indent,
+        })
+    }
+
+    let lines: Vec<&str> = markdown.split_inclusive('\n').collect();
+    // Handle final line that may lack trailing newline.
+    // split_inclusive already keeps the original chunks, including a
+    // final chunk without '\n' if the input doesn't end with one.
+
+    // First pass: classify every line.
+    let fence_info: Vec<Option<FenceLine>> = lines.iter().map(|l| parse_fence_line(l)).collect();
+
+    // Second pass: pair openers with closers using a stack, recording
+    // (opener_idx, closer_idx) pairs plus the max fence length found between
+    // them.
+    struct StackEntry {
+        line_idx: usize,
+        fence: FenceLine,
+    }
+
+    let mut stack: Vec<StackEntry> = Vec::new();
+    // Paired blocks: (opener_line, closer_line, max_inner_fence_len)
+    let mut pairs: Vec<(usize, usize, usize)> = Vec::new();
+
+    for (i, fi) in fence_info.iter().enumerate() {
+        let Some(fl) = fi else { continue };
+
+        if fl.has_info {
+            // Labeled fence ⇒ always an opener.
+            stack.push(StackEntry {
+                line_idx: i,
+                fence: fl.clone(),
+            });
+        } else {
+            // Bare fence ⇒ try to close the top of the stack if compatible.
+            let closes_top = stack
+                .last()
+                .is_some_and(|top| top.fence.char == fl.char && fl.len >= top.fence.len);
+            if closes_top {
+                let opener = stack.pop().unwrap();
+                // Find max fence length of any fence line strictly between
+                // opener and closer (these are the nested fences).
+                let inner_max = fence_info[opener.line_idx + 1..i]
+                    .iter()
+                    .filter_map(|fi| fi.as_ref().map(|f| f.len))
+                    .max()
+                    .unwrap_or(0);
+                pairs.push((opener.line_idx, i, inner_max));
+            } else {
+                // Treat as opener.
+                stack.push(StackEntry {
+                    line_idx: i,
+                    fence: fl.clone(),
+                });
+            }
+        }
+    }
+
+    // Determine which lines need rewriting.  A pair needs rewriting when
+    // its opener length <= max inner fence length.
+    struct Rewrite {
+        char: char,
+        new_len: usize,
+        indent: usize,
+    }
+    let mut rewrites: std::collections::HashMap<usize, Rewrite> = std::collections::HashMap::new();
+
+    for (opener_idx, closer_idx, inner_max) in &pairs {
+        let opener_fl = fence_info[*opener_idx].as_ref().unwrap();
+        if opener_fl.len <= *inner_max {
+            let new_len = inner_max + 1;
+            let info_part = {
+                let trimmed = lines[*opener_idx]
+                    .trim_end_matches('\n')
+                    .trim_end_matches('\r');
+                let rest = &trimmed[opener_fl.indent..];
+                rest[opener_fl.len..].to_string()
+            };
+            rewrites.insert(
+                *opener_idx,
+                Rewrite {
+                    char: opener_fl.char,
+                    new_len,
+                    indent: opener_fl.indent,
+                },
+            );
+            let closer_fl = fence_info[*closer_idx].as_ref().unwrap();
+            rewrites.insert(
+                *closer_idx,
+                Rewrite {
+                    char: closer_fl.char,
+                    new_len,
+                    indent: closer_fl.indent,
+                },
+            );
+            // Store info string only in the opener; closer keeps the trailing
+            // portion which is already handled through the original line.
+            // Actually, we rebuild both lines from scratch below, including
+            // the info string for the opener.
+            let _ = info_part; // consumed in rebuild
+        }
+    }
+
+    if rewrites.is_empty() {
+        return markdown.to_string();
+    }
+
+    // Rebuild.
+    let mut out = String::with_capacity(markdown.len() + rewrites.len() * 4);
+    for (i, line) in lines.iter().enumerate() {
+        if let Some(rw) = rewrites.get(&i) {
+            let fence_str: String = std::iter::repeat(rw.char).take(rw.new_len).collect();
+            let indent_str: String = std::iter::repeat(' ').take(rw.indent).collect();
+            // Recover the original info string (if any) and trailing newline.
+            let trimmed = line.trim_end_matches('\n').trim_end_matches('\r');
+            let fi = fence_info[i].as_ref().unwrap();
+            let info = &trimmed[fi.indent + fi.len..];
+            let trailing = &line[trimmed.len()..];
+            out.push_str(&indent_str);
+            out.push_str(&fence_str);
+            out.push_str(info);
+            out.push_str(trailing);
+        } else {
+            out.push_str(line);
+        }
+    }
+    out
+}
+
 fn find_stream_safe_boundary(markdown: &str) -> Option<usize> {
-    let mut in_fence = false;
+    let mut open_fence: Option<FenceMarker> = None;
     let mut last_boundary = None;
 
     for (offset, line) in markdown.split_inclusive('\n').scan(0usize, |cursor, line| {
@@ -643,20 +816,21 @@ fn find_stream_safe_boundary(markdown: &str) -> Option<usize> {
         *cursor += line.len();
         Some((start, line))
     }) {
-        let trimmed = line.trim_start();
-        if trimmed.starts_with("```") || trimmed.starts_with("~~~") {
-            in_fence = !in_fence;
-            if !in_fence {
+        let line_without_newline = line.trim_end_matches('\n');
+        if let Some(opener) = open_fence {
+            if line_closes_fence(line_without_newline, opener) {
+                open_fence = None;
                 last_boundary = Some(offset + line.len());
             }
             continue;
         }
 
-        if in_fence {
+        if let Some(opener) = parse_fence_opener(line_without_newline) {
+            open_fence = Some(opener);
             continue;
         }
 
-        if trimmed.is_empty() {
+        if line_without_newline.trim().is_empty() {
             last_boundary = Some(offset + line.len());
         }
     }
@@ -664,6 +838,46 @@ fn find_stream_safe_boundary(markdown: &str) -> Option<usize> {
     last_boundary
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+struct FenceMarker {
+    character: char,
+    length: usize,
+}
+
+fn parse_fence_opener(line: &str) -> Option<FenceMarker> {
+    let indent = line.chars().take_while(|c| *c == ' ').count();
+    if indent > 3 {
+        return None;
+    }
+    let rest = &line[indent..];
+    let character = rest.chars().next()?;
+    if character != '`' && character != '~' {
+        return None;
+    }
+    let length = rest.chars().take_while(|c| *c == character).count();
+    if length < 3 {
+        return None;
+    }
+    let info_string = &rest[length..];
+    if character == '`' && info_string.contains('`') {
+        return None;
+    }
+    Some(FenceMarker { character, length })
+}
+
+fn line_closes_fence(line: &str, opener: FenceMarker) -> bool {
+    let indent = line.chars().take_while(|c| *c == ' ').count();
+    if indent > 3 {
+        return false;
+    }
+    let rest = &line[indent..];
+    let length = rest.chars().take_while(|c| *c == opener.character).count();
+    if length < opener.length {
+        return false;
+    }
+    rest[length..].chars().all(|c| c == ' ' || c == '\t')
+}
+
 fn visible_width(input: &str) -> usize {
     strip_ansi(input).chars().count()
 }
@@ -778,6 +992,60 @@ mod tests {
         assert!(strip_ansi(&code).contains("fn main()"));
     }
 
+    #[test]
+    fn streaming_state_holds_outer_fence_with_nested_inner_fence() {
+        let renderer = TerminalRenderer::new();
+        let mut state = MarkdownStreamState::default();
+
+        assert_eq!(
+            state.push(&renderer, "````markdown\n```rust\nfn inner() {}\n"),
+            None,
+            "inner triple backticks must not close the outer four-backtick fence"
+        );
+        assert_eq!(
+            state.push(&renderer, "```\n"),
+            None,
+            "closing the inner fence must not flush the outer fence"
+        );
+        let flushed = state
+            .push(&renderer, "````\n")
+            .expect("closing the outer four-backtick fence flushes the buffered block");
+        let plain_text = strip_ansi(&flushed);
+        assert!(plain_text.contains("fn inner()"));
+        assert!(plain_text.contains("```rust"));
+    }
+
+    #[test]
+    fn streaming_state_distinguishes_backtick_and_tilde_fences() {
+        let renderer = TerminalRenderer::new();
+        let mut state = MarkdownStreamState::default();
+
+        assert_eq!(state.push(&renderer, "~~~text\n"), None);
+        assert_eq!(
+            state.push(&renderer, "```\nstill inside tilde fence\n"),
+            None,
+            "a backtick fence cannot close a tilde-opened fence"
+        );
+        assert_eq!(state.push(&renderer, "```\n"), None);
+        let flushed = state
+            .push(&renderer, "~~~\n")
+            .expect("matching tilde marker closes the fence");
+        let plain_text = strip_ansi(&flushed);
+        assert!(plain_text.contains("still inside tilde fence"));
+    }
+
+    #[test]
+    fn renders_nested_fenced_code_block_preserves_inner_markers() {
+        let terminal_renderer = TerminalRenderer::new();
+        let markdown_output =
+            terminal_renderer.markdown_to_ansi("````markdown\n```rust\nfn nested() {}\n```\n````");
+        let plain_text = strip_ansi(&markdown_output);
+
+        assert!(plain_text.contains("╭─ markdown"));
+        assert!(plain_text.contains("```rust"));
+        assert!(plain_text.contains("fn nested()"));
+    }
+
     #[test]
     fn spinner_advances_frames() {
         let terminal_renderer = TerminalRenderer::new();

rust/crates/rusty-claude-cli/tests/compact_output.rs

@@ -0,0 +1,159 @@
+use std::fs;
+use std::path::PathBuf;
+use std::process::{Command, Output};
+use std::sync::atomic::{AtomicU64, Ordering};
+use std::time::{SystemTime, UNIX_EPOCH};
+
+use mock_anthropic_service::{MockAnthropicService, SCENARIO_PREFIX};
+
+static TEMP_COUNTER: AtomicU64 = AtomicU64::new(0);
+
+#[test]
+fn compact_flag_prints_only_final_assistant_text_without_tool_call_details() {
+    // given a workspace pointed at the mock Anthropic service and a fixture file
+    // that the read_file_roundtrip scenario will fetch through a tool call
+    let runtime = tokio::runtime::Runtime::new().expect("tokio runtime should build");
+    let server = runtime
+        .block_on(MockAnthropicService::spawn())
+        .expect("mock service should start");
+    let base_url = server.base_url();
+
+    let workspace = unique_temp_dir("compact-read-file");
+    let config_home = workspace.join("config-home");
+    let home = workspace.join("home");
+    fs::create_dir_all(&workspace).expect("workspace should exist");
+    fs::create_dir_all(&config_home).expect("config home should exist");
+    fs::create_dir_all(&home).expect("home should exist");
+    fs::write(workspace.join("fixture.txt"), "alpha parity line\n").expect("fixture should write");
+
+    // when we run claw in compact text mode against a tool-using scenario
+    let prompt = format!("{SCENARIO_PREFIX}read_file_roundtrip");
+    let output = run_claw(
+        &workspace,
+        &config_home,
+        &home,
+        &base_url,
+        &[
+            "--model",
+            "sonnet",
+            "--permission-mode",
+            "read-only",
+            "--allowedTools",
+            "read_file",
+            "--compact",
+            &prompt,
+        ],
+    );
+
+    // then the command exits successfully and stdout contains exactly the final
+    // assistant text with no tool call IDs, JSON envelopes, or spinner output
+    assert!(
+        output.status.success(),
+        "compact run should succeed\nstdout:\n{}\n\nstderr:\n{}",
+        String::from_utf8_lossy(&output.stdout),
+        String::from_utf8_lossy(&output.stderr),
+    );
+    let stdout = String::from_utf8(output.stdout).expect("stdout should be utf8");
+    let trimmed = stdout.trim_end_matches('\n');
+    assert_eq!(
+        trimmed, "read_file roundtrip complete: alpha parity line",
+        "compact stdout should contain only the final assistant text"
+    );
+    assert!(
+        !stdout.contains("toolu_"),
+        "compact stdout must not leak tool_use_id ({stdout:?})"
+    );
+    assert!(
+        !stdout.contains("\"tool_uses\""),
+        "compact stdout must not leak json envelopes ({stdout:?})"
+    );
+    assert!(
+        !stdout.contains("Thinking"),
+        "compact stdout must not include the spinner banner ({stdout:?})"
+    );
+
+    fs::remove_dir_all(&workspace).expect("workspace cleanup should succeed");
+}
+
+#[test]
+fn compact_flag_streaming_text_only_emits_final_message_text() {
+    // given a workspace pointed at the mock Anthropic service running the
+    // streaming_text scenario which only emits a single assistant text block
+    let runtime = tokio::runtime::Runtime::new().expect("tokio runtime should build");
+    let server = runtime
+        .block_on(MockAnthropicService::spawn())
+        .expect("mock service should start");
+    let base_url = server.base_url();
+
+    let workspace = unique_temp_dir("compact-streaming-text");
+    let config_home = workspace.join("config-home");
+    let home = workspace.join("home");
+    fs::create_dir_all(&workspace).expect("workspace should exist");
+    fs::create_dir_all(&config_home).expect("config home should exist");
+    fs::create_dir_all(&home).expect("home should exist");
+
+    // when we invoke claw with --compact for the streaming text scenario
+    let prompt = format!("{SCENARIO_PREFIX}streaming_text");
+    let output = run_claw(
+        &workspace,
+        &config_home,
+        &home,
+        &base_url,
+        &[
+            "--model",
+            "sonnet",
+            "--permission-mode",
+            "read-only",
+            "--compact",
+            &prompt,
+        ],
+    );
+
+    // then stdout should be exactly the assistant text followed by a newline
+    assert!(
+        output.status.success(),
+        "compact streaming run should succeed\nstdout:\n{}\n\nstderr:\n{}",
+        String::from_utf8_lossy(&output.stdout),
+        String::from_utf8_lossy(&output.stderr),
+    );
+    let stdout = String::from_utf8(output.stdout).expect("stdout should be utf8");
+    assert_eq!(
+        stdout, "Mock streaming says hello from the parity harness.\n",
+        "compact streaming stdout should contain only the final assistant text"
+    );
+
+    fs::remove_dir_all(&workspace).expect("workspace cleanup should succeed");
+}
+
+fn run_claw(
+    cwd: &std::path::Path,
+    config_home: &std::path::Path,
+    home: &std::path::Path,
+    base_url: &str,
+    args: &[&str],
+) -> Output {
+    let mut command = Command::new(env!("CARGO_BIN_EXE_claw"));
+    command
+        .current_dir(cwd)
+        .env_clear()
+        .env("ANTHROPIC_API_KEY", "test-compact-key")
+        .env("ANTHROPIC_BASE_URL", base_url)
+        .env("CLAW_CONFIG_HOME", config_home)
+        .env("HOME", home)
+        .env("NO_COLOR", "1")
+        .env("PATH", "/usr/bin:/bin")
+        .args(args);
+    command.output().expect("claw should launch")
+}
+
+fn unique_temp_dir(label: &str) -> PathBuf {
+    let millis = SystemTime::now()
+        .duration_since(UNIX_EPOCH)
+        .expect("clock should be after epoch")
+        .as_millis();
+    let counter = TEMP_COUNTER.fetch_add(1, Ordering::Relaxed);
+    std::env::temp_dir().join(format!(
+        "claw-compact-{label}-{}-{millis}-{counter}",
+        std::process::id()
+    ))
+}

rust/crates/tools/Cargo.toml

@@ -8,6 +8,7 @@ publish.workspace = true
 [dependencies]
 api = { path = "../api" }
 commands = { path = "../commands" }
+flate2 = "1"
 plugins = { path = "../plugins" }
 runtime = { path = "../runtime" }
 reqwest = { version = "0.12", default-features = false, features = ["blocking", "rustls-tls"] }

rust/crates/tools/src/lib.rs

@@ -4,8 +4,8 @@ use std::process::Command;
 use std::time::{Duration, Instant};
 
 use api::{
-    max_tokens_for_model, resolve_model_alias, ContentBlockDelta, InputContentBlock, InputMessage,
-    MessageRequest, MessageResponse, OutputContentBlock, ProviderClient,
+    max_tokens_for_model, resolve_model_alias, ApiError, ContentBlockDelta, InputContentBlock,
+    InputMessage, MessageRequest, MessageResponse, OutputContentBlock, ProviderClient,
     StreamEvent as ApiStreamEvent, ToolChoice, ToolDefinition, ToolResultContentBlock,
 };
 use plugins::PluginTool;
@@ -22,10 +22,11 @@ use runtime::{
     team_cron_registry::{CronRegistry, TeamRegistry},
     worker_boot::{WorkerReadySnapshot, WorkerRegistry},
     write_file, ApiClient, ApiRequest, AssistantEvent, BashCommandInput, BashCommandOutput,
-    BranchFreshness, ContentBlock, ConversationMessage, ConversationRuntime, GrepSearchInput,
-    LaneCommitProvenance, LaneEvent, LaneEventBlocker, LaneEventName, LaneEventStatus,
-    LaneFailureClass, McpDegradedReport, MessageRole, PermissionMode, PermissionPolicy,
-    PromptCacheEvent, RuntimeError, Session, TaskPacket, ToolError, ToolExecutor,
+    BranchFreshness, ConfigLoader, ContentBlock, ConversationMessage, ConversationRuntime,
+    GrepSearchInput, LaneCommitProvenance, LaneEvent, LaneEventBlocker, LaneEventName,
+    LaneEventStatus, LaneFailureClass, McpDegradedReport, MessageRole, PermissionMode,
+    PermissionPolicy, PromptCacheEvent, ProviderFallbackConfig, RuntimeError, Session, TaskPacket,
+    ToolError, ToolExecutor,
 };
 use serde::{Deserialize, Serialize};
 use serde_json::{json, Value};
@@ -3699,29 +3700,73 @@ fn classify_lane_failure(error: &str) -> LaneFailureClass {
     }
 }
 
+struct ProviderEntry {
+    model: String,
+    client: ProviderClient,
+}
+
 struct ProviderRuntimeClient {
     runtime: tokio::runtime::Runtime,
-    client: ProviderClient,
-    model: String,
+    chain: Vec<ProviderEntry>,
     allowed_tools: BTreeSet<String>,
 }
 
 impl ProviderRuntimeClient {
     #[allow(clippy::needless_pass_by_value)]
     fn new(model: String, allowed_tools: BTreeSet<String>) -> Result<Self, String> {
-        let model = resolve_model_alias(&model).clone();
-        let client = ProviderClient::from_model(&model).map_err(|error| error.to_string())?;
+        let fallback_config = load_provider_fallback_config();
+        Self::new_with_fallback_config(model, allowed_tools, &fallback_config)
+    }
+
+    #[allow(clippy::needless_pass_by_value)]
+    fn new_with_fallback_config(
+        model: String,
+        allowed_tools: BTreeSet<String>,
+        fallback_config: &ProviderFallbackConfig,
+    ) -> Result<Self, String> {
+        let primary_model = fallback_config
+            .primary()
+            .map(str::to_string)
+            .unwrap_or(model);
+        let primary = build_provider_entry(&primary_model)?;
+        let mut chain = vec![primary];
+        for fallback_model in fallback_config.fallbacks() {
+            match build_provider_entry(fallback_model) {
+                Ok(entry) => chain.push(entry),
+                Err(error) => {
+                    eprintln!(
+                        "warning: skipping unavailable fallback provider {fallback_model}: {error}"
+                    );
+                }
+            }
+        }
         Ok(Self {
             runtime: tokio::runtime::Runtime::new().map_err(|error| error.to_string())?,
-            client,
-            model,
+            chain,
             allowed_tools,
         })
     }
 }
 
+fn build_provider_entry(model: &str) -> Result<ProviderEntry, String> {
+    let resolved = resolve_model_alias(model).clone();
+    let client = ProviderClient::from_model(&resolved).map_err(|error| error.to_string())?;
+    Ok(ProviderEntry {
+        model: resolved,
+        client,
+    })
+}
+
+fn load_provider_fallback_config() -> ProviderFallbackConfig {
+    std::env::current_dir()
+        .ok()
+        .and_then(|cwd| ConfigLoader::default_for(cwd).load().ok())
+        .map_or_else(ProviderFallbackConfig::default, |config| {
+            config.provider_fallbacks().clone()
+        })
+}
+
 impl ApiClient for ProviderRuntimeClient {
-    #[allow(clippy::too_many_lines)]
     fn stream(&mut self, request: ApiRequest) -> Result<Vec<AssistantEvent>, RuntimeError> {
         let tools = tool_specs_for_allowed_tools(Some(&self.allowed_tools))
             .into_iter()
@@ -3731,106 +3776,129 @@ impl ApiClient for ProviderRuntimeClient {
                 input_schema: spec.input_schema,
             })
             .collect::<Vec<_>>();
-        let message_request = MessageRequest {
-            model: self.model.clone(),
-            max_tokens: max_tokens_for_model(&self.model),
-            messages: convert_messages(&request.messages),
-            system: (!request.system_prompt.is_empty()).then(|| request.system_prompt.join("\n\n")),
-            tools: (!tools.is_empty()).then_some(tools),
-            tool_choice: (!self.allowed_tools.is_empty()).then_some(ToolChoice::Auto),
-            stream: true,
-        };
+        let messages = convert_messages(&request.messages);
+        let system = (!request.system_prompt.is_empty()).then(|| request.system_prompt.join("\n\n"));
+        let tool_choice = (!self.allowed_tools.is_empty()).then_some(ToolChoice::Auto);
 
-        self.runtime.block_on(async {
-            let mut stream = self
-                .client
-                .stream_message(&message_request)
-                .await
-                .map_err(|error| RuntimeError::new(error.to_string()))?;
-            let mut events = Vec::new();
-            let mut pending_tools: BTreeMap<u32, (String, String, String)> = BTreeMap::new();
-            let mut saw_stop = false;
+        let runtime = &self.runtime;
+        let chain = &self.chain;
+        let mut last_error: Option<ApiError> = None;
+        for (index, entry) in chain.iter().enumerate() {
+            let message_request = MessageRequest {
+                model: entry.model.clone(),
+                max_tokens: max_tokens_for_model(&entry.model),
+                messages: messages.clone(),
+                system: system.clone(),
+                tools: (!tools.is_empty()).then(|| tools.clone()),
+                tool_choice: tool_choice.clone(),
+                stream: true,
+            };
 
-            while let Some(event) = stream
-                .next_event()
-                .await
-                .map_err(|error| RuntimeError::new(error.to_string()))?
-            {
-                match event {
-                    ApiStreamEvent::MessageStart(start) => {
-                        for block in start.message.content {
-                            push_output_block(block, 0, &mut events, &mut pending_tools, true);
-                        }
-                    }
-                    ApiStreamEvent::ContentBlockStart(start) => {
-                        push_output_block(
-                            start.content_block,
-                            start.index,
-                            &mut events,
-                            &mut pending_tools,
-                            true,
-                        );
-                    }
-                    ApiStreamEvent::ContentBlockDelta(delta) => match delta.delta {
-                        ContentBlockDelta::TextDelta { text } => {
-                            if !text.is_empty() {
-                                events.push(AssistantEvent::TextDelta(text));
-                            }
-                        }
-                        ContentBlockDelta::InputJsonDelta { partial_json } => {
-                            if let Some((_, _, input)) = pending_tools.get_mut(&delta.index) {
-                                input.push_str(&partial_json);
-                            }
-                        }
-                        ContentBlockDelta::ThinkingDelta { .. }
-                        | ContentBlockDelta::SignatureDelta { .. } => {}
-                    },
-                    ApiStreamEvent::ContentBlockStop(stop) => {
-                        if let Some((id, name, input)) = pending_tools.remove(&stop.index) {
-                            events.push(AssistantEvent::ToolUse { id, name, input });
-                        }
-                    }
-                    ApiStreamEvent::MessageDelta(delta) => {
-                        events.push(AssistantEvent::Usage(delta.usage.token_usage()));
-                    }
-                    ApiStreamEvent::MessageStop(_) => {
-                        saw_stop = true;
-                        events.push(AssistantEvent::MessageStop);
-                    }
+            let attempt = runtime.block_on(stream_with_provider(&entry.client, &message_request));
+            match attempt {
+                Ok(events) => return Ok(events),
+                Err(error) if error.is_retryable() && index + 1 < chain.len() => {
+                    eprintln!(
+                        "provider {} failed with retryable error, falling back: {error}",
+                        entry.model
+                    );
+                    last_error = Some(error);
+                    continue;
+                }
+                Err(error) => return Err(RuntimeError::new(error.to_string())),
+            }
+        }
+
+        Err(RuntimeError::new(
+            last_error
+                .map(|error| error.to_string())
+                .unwrap_or_else(|| String::from("provider chain exhausted with no attempts")),
+        ))
+    }
+}
+
+#[allow(clippy::too_many_lines)]
+async fn stream_with_provider(
+    client: &ProviderClient,
+    message_request: &MessageRequest,
+) -> Result<Vec<AssistantEvent>, ApiError> {
+    let mut stream = client.stream_message(message_request).await?;
+    let mut events = Vec::new();
+    let mut pending_tools: BTreeMap<u32, (String, String, String)> = BTreeMap::new();
+    let mut saw_stop = false;
+
+    while let Some(event) = stream.next_event().await? {
+        match event {
+            ApiStreamEvent::MessageStart(start) => {
+                for block in start.message.content {
+                    push_output_block(block, 0, &mut events, &mut pending_tools, true);
                 }
             }
-
-            push_prompt_cache_record(&self.client, &mut events);
-
-            if !saw_stop
-                && events.iter().any(|event| {
-                    matches!(event, AssistantEvent::TextDelta(text) if !text.is_empty())
-                        || matches!(event, AssistantEvent::ToolUse { .. })
-                })
-            {
+            ApiStreamEvent::ContentBlockStart(start) => {
+                push_output_block(
+                    start.content_block,
+                    start.index,
+                    &mut events,
+                    &mut pending_tools,
+                    true,
+                );
+            }
+            ApiStreamEvent::ContentBlockDelta(delta) => match delta.delta {
+                ContentBlockDelta::TextDelta { text } => {
+                    if !text.is_empty() {
+                        events.push(AssistantEvent::TextDelta(text));
+                    }
+                }
+                ContentBlockDelta::InputJsonDelta { partial_json } => {
+                    if let Some((_, _, input)) = pending_tools.get_mut(&delta.index) {
+                        input.push_str(&partial_json);
+                    }
+                }
+                ContentBlockDelta::ThinkingDelta { .. }
+                | ContentBlockDelta::SignatureDelta { .. } => {}
+            },
+            ApiStreamEvent::ContentBlockStop(stop) => {
+                if let Some((id, name, input)) = pending_tools.remove(&stop.index) {
+                    events.push(AssistantEvent::ToolUse { id, name, input });
+                }
+            }
+            ApiStreamEvent::MessageDelta(delta) => {
+                events.push(AssistantEvent::Usage(delta.usage.token_usage()));
+            }
+            ApiStreamEvent::MessageStop(_) => {
+                saw_stop = true;
                 events.push(AssistantEvent::MessageStop);
             }
-
-            if events
-                .iter()
-                .any(|event| matches!(event, AssistantEvent::MessageStop))
-            {
-                return Ok(events);
-            }
-
-            let response = self
-                .client
-                .send_message(&MessageRequest {
-                    stream: false,
-                    ..message_request.clone()
-                })
-                .await
-                .map_err(|error| RuntimeError::new(error.to_string()))?;
-            let mut events = response_to_events(response);
-            push_prompt_cache_record(&self.client, &mut events);
-            Ok(events)
-        })
+        }
     }
+
+    push_prompt_cache_record(client, &mut events);
+
+    if !saw_stop
+        && events.iter().any(|event| {
+            matches!(event, AssistantEvent::TextDelta(text) if !text.is_empty())
+                || matches!(event, AssistantEvent::ToolUse { .. })
+        })
+    {
+        events.push(AssistantEvent::MessageStop);
+    }
+
+    if events
+        .iter()
+        .any(|event| matches!(event, AssistantEvent::MessageStop))
+    {
+        return Ok(events);
+    }
+
+    let response = client
+        .send_message(&MessageRequest {
+            stream: false,
+            ..message_request.clone()
+        })
+        .await?;
+    let mut events = response_to_events(response);
+    push_prompt_cache_record(client, &mut events);
+    Ok(events)
 }
 
 struct SubagentToolExecutor {
@@ -5238,6 +5306,7 @@ fn parse_skill_description(contents: &str) -> Option<String> {
 }
 
 pub mod lane_completion;
+pub mod pdf_extract;
 
 #[cfg(test)]
 mod tests {
@@ -5257,8 +5326,10 @@ mod tests {
         derive_agent_state, execute_agent_with_spawn, execute_tool, final_assistant_text,
         maybe_commit_provenance, mvp_tool_specs, permission_mode_from_plugin,
         persist_agent_terminal_state, push_output_block, run_task_packet, AgentInput, AgentJob,
-        GlobalToolRegistry, LaneEventName, LaneFailureClass, SubagentToolExecutor,
+        GlobalToolRegistry, LaneEventName, LaneFailureClass, ProviderRuntimeClient,
+        SubagentToolExecutor,
     };
+    use runtime::ProviderFallbackConfig;
     use api::OutputContentBlock;
     use runtime::{
         permission_enforcer::PermissionEnforcer, ApiRequest, AssistantEvent, ConversationRuntime,
@@ -7769,6 +7840,151 @@ printf 'pwsh:%s' "$1"
         assert_eq!(output["stdout"], "ok");
     }
 
+    #[test]
+    fn provider_runtime_client_chain_uses_only_primary_when_no_fallbacks_configured() {
+        // given
+        let _guard = env_lock()
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        let original_anthropic = std::env::var_os("ANTHROPIC_API_KEY");
+        std::env::set_var("ANTHROPIC_API_KEY", "anthropic-test-key");
+        let fallback_config = ProviderFallbackConfig::default();
+
+        // when
+        let client = ProviderRuntimeClient::new_with_fallback_config(
+            "claude-sonnet-4-6".to_string(),
+            BTreeSet::new(),
+            &fallback_config,
+        )
+        .expect("primary-only chain should construct");
+
+        // then
+        assert_eq!(client.chain.len(), 1);
+        assert_eq!(client.chain[0].model, "claude-sonnet-4-6");
+
+        match original_anthropic {
+            Some(value) => std::env::set_var("ANTHROPIC_API_KEY", value),
+            None => std::env::remove_var("ANTHROPIC_API_KEY"),
+        }
+    }
+
+    #[test]
+    fn provider_runtime_client_chain_appends_configured_fallbacks_in_order() {
+        // given
+        let _guard = env_lock()
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        let original_anthropic = std::env::var_os("ANTHROPIC_API_KEY");
+        let original_xai = std::env::var_os("XAI_API_KEY");
+        std::env::set_var("ANTHROPIC_API_KEY", "anthropic-test-key");
+        std::env::set_var("XAI_API_KEY", "xai-test-key");
+        let fallback_config = ProviderFallbackConfig::new(
+            None,
+            vec!["grok-3".to_string(), "grok-3-mini".to_string()],
+        );
+
+        // when
+        let client = ProviderRuntimeClient::new_with_fallback_config(
+            "claude-sonnet-4-6".to_string(),
+            BTreeSet::new(),
+            &fallback_config,
+        )
+        .expect("chain with fallbacks should construct");
+
+        // then
+        assert_eq!(client.chain.len(), 3);
+        assert_eq!(client.chain[0].model, "claude-sonnet-4-6");
+        assert_eq!(client.chain[1].model, "grok-3");
+        assert_eq!(client.chain[2].model, "grok-3-mini");
+
+        match original_anthropic {
+            Some(value) => std::env::set_var("ANTHROPIC_API_KEY", value),
+            None => std::env::remove_var("ANTHROPIC_API_KEY"),
+        }
+        match original_xai {
+            Some(value) => std::env::set_var("XAI_API_KEY", value),
+            None => std::env::remove_var("XAI_API_KEY"),
+        }
+    }
+
+    #[test]
+    fn provider_runtime_client_chain_primary_override_replaces_constructor_model() {
+        // given
+        let _guard = env_lock()
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        let original_anthropic = std::env::var_os("ANTHROPIC_API_KEY");
+        let original_xai = std::env::var_os("XAI_API_KEY");
+        std::env::set_var("ANTHROPIC_API_KEY", "anthropic-test-key");
+        std::env::set_var("XAI_API_KEY", "xai-test-key");
+        let fallback_config = ProviderFallbackConfig::new(
+            Some("grok-3".to_string()),
+            vec!["claude-sonnet-4-6".to_string()],
+        );
+
+        // when
+        let client = ProviderRuntimeClient::new_with_fallback_config(
+            "claude-haiku-4-5-20251213".to_string(),
+            BTreeSet::new(),
+            &fallback_config,
+        )
+        .expect("chain with primary override should construct");
+
+        // then
+        assert_eq!(client.chain.len(), 2);
+        assert_eq!(client.chain[0].model, "grok-3");
+        assert_eq!(client.chain[1].model, "claude-sonnet-4-6");
+
+        match original_anthropic {
+            Some(value) => std::env::set_var("ANTHROPIC_API_KEY", value),
+            None => std::env::remove_var("ANTHROPIC_API_KEY"),
+        }
+        match original_xai {
+            Some(value) => std::env::set_var("XAI_API_KEY", value),
+            None => std::env::remove_var("XAI_API_KEY"),
+        }
+    }
+
+    #[test]
+    fn provider_runtime_client_chain_skips_fallbacks_missing_credentials() {
+        // given
+        let _guard = env_lock()
+            .lock()
+            .unwrap_or_else(std::sync::PoisonError::into_inner);
+        let original_anthropic = std::env::var_os("ANTHROPIC_API_KEY");
+        let original_xai = std::env::var_os("XAI_API_KEY");
+        std::env::set_var("ANTHROPIC_API_KEY", "anthropic-test-key");
+        std::env::remove_var("XAI_API_KEY");
+        let fallback_config = ProviderFallbackConfig::new(
+            None,
+            vec![
+                "grok-3".to_string(),
+                "claude-haiku-4-5-20251213".to_string(),
+            ],
+        );
+
+        // when
+        let client = ProviderRuntimeClient::new_with_fallback_config(
+            "claude-sonnet-4-6".to_string(),
+            BTreeSet::new(),
+            &fallback_config,
+        )
+        .expect("chain construction should not fail when only some fallbacks are unavailable");
+
+        // then
+        assert_eq!(client.chain.len(), 2);
+        assert_eq!(client.chain[0].model, "claude-sonnet-4-6");
+        assert_eq!(client.chain[1].model, "claude-haiku-4-5-20251213");
+
+        match original_anthropic {
+            Some(value) => std::env::set_var("ANTHROPIC_API_KEY", value),
+            None => std::env::remove_var("ANTHROPIC_API_KEY"),
+        }
+        if let Some(value) = original_xai {
+            std::env::set_var("XAI_API_KEY", value);
+        }
+    }
+
     #[test]
     fn run_task_packet_creates_packet_backed_task() {
         let result = run_task_packet(TaskPacket {

rust/crates/tools/src/pdf_extract.rs

@@ -0,0 +1,548 @@
+//! Minimal PDF text extraction.
+//!
+//! Reads a PDF file, locates `/Contents` stream objects, decompresses with
+//! flate2 when the stream uses `/FlateDecode`, and extracts text operators
+//! found between `BT` / `ET` markers.
+
+use std::io::Read as _;
+use std::path::Path;
+
+/// Extract all readable text from a PDF file.
+///
+/// Returns the concatenated text found inside BT/ET operators across all
+/// content streams.  Non-text pages or encrypted PDFs yield an empty string
+/// rather than an error.
+pub fn extract_text(path: &Path) -> Result<String, String> {
+    let data = std::fs::read(path).map_err(|e| format!("failed to read PDF: {e}"))?;
+    Ok(extract_text_from_bytes(&data))
+}
+
+/// Core extraction from raw PDF bytes — useful for testing without touching the
+/// filesystem.
+pub(crate) fn extract_text_from_bytes(data: &[u8]) -> String {
+    let mut all_text = String::new();
+    let mut offset = 0;
+
+    while offset < data.len() {
+        let Some(stream_start) = find_subsequence(&data[offset..], b"stream") else {
+            break;
+        };
+        let abs_start = offset + stream_start;
+
+        // Determine the byte offset right after "stream\r\n" or "stream\n".
+        let content_start = skip_stream_eol(data, abs_start + b"stream".len());
+
+        let Some(end_rel) = find_subsequence(&data[content_start..], b"endstream") else {
+            break;
+        };
+        let content_end = content_start + end_rel;
+
+        // Look backwards from "stream" for a FlateDecode hint in the object
+        // dictionary.  We scan at most 512 bytes before the stream keyword.
+        let dict_window_start = abs_start.saturating_sub(512);
+        let dict_window = &data[dict_window_start..abs_start];
+        let is_flate = find_subsequence(dict_window, b"FlateDecode").is_some();
+
+        // Only process streams whose parent dictionary references /Contents or
+        // looks like a page content stream (contains /Length).  We intentionally
+        // keep this loose to cover both inline and referenced content streams.
+        let raw = &data[content_start..content_end];
+        let decompressed;
+        let stream_bytes: &[u8] = if is_flate {
+            if let Ok(buf) = inflate(raw) {
+                decompressed = buf;
+                &decompressed
+            } else {
+                offset = content_end;
+                continue;
+            }
+        } else {
+            raw
+        };
+
+        let text = extract_bt_et_text(stream_bytes);
+        if !text.is_empty() {
+            if !all_text.is_empty() {
+                all_text.push('\n');
+            }
+            all_text.push_str(&text);
+        }
+
+        offset = content_end;
+    }
+
+    all_text
+}
+
+/// Inflate (zlib / deflate) compressed data via `flate2`.
+fn inflate(data: &[u8]) -> Result<Vec<u8>, String> {
+    let mut decoder = flate2::read::ZlibDecoder::new(data);
+    let mut buf = Vec::new();
+    decoder
+        .read_to_end(&mut buf)
+        .map_err(|e| format!("flate2 inflate error: {e}"))?;
+    Ok(buf)
+}
+
+/// Extract text from PDF content-stream operators between BT and ET markers.
+///
+/// Handles the common text-showing operators:
+/// - `Tj`  — show a string
+/// - `TJ`  — show an array of strings/numbers
+/// - `'`   — move to next line and show string
+/// - `"`   — set spacing, move to next line and show string
+fn extract_bt_et_text(stream: &[u8]) -> String {
+    let text = String::from_utf8_lossy(stream);
+    let mut result = String::new();
+    let mut in_bt = false;
+
+    for line in text.lines() {
+        let trimmed = line.trim();
+        if trimmed == "BT" {
+            in_bt = true;
+            continue;
+        }
+        if trimmed == "ET" {
+            in_bt = false;
+            continue;
+        }
+        if !in_bt {
+            continue;
+        }
+
+        // Tj operator: (text) Tj
+        if trimmed.ends_with("Tj") {
+            if let Some(s) = extract_parenthesized_string(trimmed) {
+                if !result.is_empty() && !result.ends_with('\n') {
+                    result.push(' ');
+                }
+                result.push_str(&s);
+            }
+        }
+        // TJ operator: [ (text) 123 (text) ] TJ
+        else if trimmed.ends_with("TJ") {
+            let extracted = extract_tj_array(trimmed);
+            if !extracted.is_empty() {
+                if !result.is_empty() && !result.ends_with('\n') {
+                    result.push(' ');
+                }
+                result.push_str(&extracted);
+            }
+        }
+        // ' operator: (text) '   and   " operator: aw ac (text) "
+        else if is_newline_show_operator(trimmed) {
+            if let Some(s) = extract_parenthesized_string(trimmed) {
+                if !result.is_empty() {
+                    result.push('\n');
+                }
+                result.push_str(&s);
+            }
+        }
+    }
+
+    result
+}
+
+/// Returns `true` when `trimmed` looks like a `'` or `"` text-show operator.
+fn is_newline_show_operator(trimmed: &str) -> bool {
+    (trimmed.ends_with('\'') && trimmed.len() > 1)
+        || (trimmed.ends_with('"') && trimmed.contains('('))
+}
+
+/// Pull the text from the first `(…)` group, handling escaped parens and
+/// common PDF escape sequences.
+fn extract_parenthesized_string(input: &str) -> Option<String> {
+    let open = input.find('(')?;
+    let bytes = input.as_bytes();
+    let mut depth = 0;
+    let mut result = String::new();
+    let mut i = open;
+
+    while i < bytes.len() {
+        match bytes[i] {
+            b'(' => {
+                if depth > 0 {
+                    result.push('(');
+                }
+                depth += 1;
+            }
+            b')' => {
+                depth -= 1;
+                if depth == 0 {
+                    return Some(result);
+                }
+                result.push(')');
+            }
+            b'\\' if i + 1 < bytes.len() => {
+                i += 1;
+                match bytes[i] {
+                    b'n' => result.push('\n'),
+                    b'r' => result.push('\r'),
+                    b't' => result.push('\t'),
+                    b'\\' => result.push('\\'),
+                    b'(' => result.push('('),
+                    b')' => result.push(')'),
+                    // Octal sequences — up to 3 digits.
+                    d @ b'0'..=b'7' => {
+                        let mut octal = u32::from(d - b'0');
+                        for _ in 0..2 {
+                            if i + 1 < bytes.len()
+                                && bytes[i + 1].is_ascii_digit()
+                                && bytes[i + 1] <= b'7'
+                            {
+                                i += 1;
+                                octal = octal * 8 + u32::from(bytes[i] - b'0');
+                            } else {
+                                break;
+                            }
+                        }
+                        if let Some(ch) = char::from_u32(octal) {
+                            result.push(ch);
+                        }
+                    }
+                    other => result.push(char::from(other)),
+                }
+            }
+            ch => result.push(char::from(ch)),
+        }
+        i += 1;
+    }
+
+    None // unbalanced
+}
+
+/// Extract concatenated strings from a TJ array like `[ (Hello) -120 (World) ] TJ`.
+fn extract_tj_array(input: &str) -> String {
+    let mut result = String::new();
+    let Some(bracket_start) = input.find('[') else {
+        return result;
+    };
+    let Some(bracket_end) = input.rfind(']') else {
+        return result;
+    };
+    let inner = &input[bracket_start + 1..bracket_end];
+
+    let mut i = 0;
+    let bytes = inner.as_bytes();
+    while i < bytes.len() {
+        if bytes[i] == b'(' {
+            // Reconstruct the parenthesized string and extract it.
+            if let Some(s) = extract_parenthesized_string(&inner[i..]) {
+                result.push_str(&s);
+                // Skip past the closing paren.
+                let mut depth = 0u32;
+                for &b in &bytes[i..] {
+                    i += 1;
+                    if b == b'(' {
+                        depth += 1;
+                    } else if b == b')' {
+                        depth -= 1;
+                        if depth == 0 {
+                            break;
+                        }
+                    }
+                }
+                continue;
+            }
+        }
+        i += 1;
+    }
+
+    result
+}
+
+/// Skip past the end-of-line marker that immediately follows the `stream`
+/// keyword.  Per the PDF spec this is either `\r\n` or `\n`.
+fn skip_stream_eol(data: &[u8], pos: usize) -> usize {
+    if pos < data.len() && data[pos] == b'\r' {
+        if pos + 1 < data.len() && data[pos + 1] == b'\n' {
+            return pos + 2;
+        }
+        return pos + 1;
+    }
+    if pos < data.len() && data[pos] == b'\n' {
+        return pos + 1;
+    }
+    pos
+}
+
+/// Simple byte-subsequence search.
+fn find_subsequence(haystack: &[u8], needle: &[u8]) -> Option<usize> {
+    haystack
+        .windows(needle.len())
+        .position(|window| window == needle)
+}
+
+/// Check if a user-supplied path looks like a PDF file reference.
+#[must_use]
+pub fn looks_like_pdf_path(text: &str) -> Option<&str> {
+    for token in text.split_whitespace() {
+        let cleaned = token.trim_matches(|c: char| c == '\'' || c == '"' || c == '`');
+        if let Some(dot_pos) = cleaned.rfind('.') {
+            if cleaned[dot_pos + 1..].eq_ignore_ascii_case("pdf") && dot_pos > 0 {
+                return Some(cleaned);
+            }
+        }
+    }
+    None
+}
+
+/// Auto-extract text from a PDF path mentioned in a user prompt.
+///
+/// Returns `Some((path, extracted_text))` when a `.pdf` path is detected and
+/// the file exists, otherwise `None`.
+#[must_use]
+pub fn maybe_extract_pdf_from_prompt(prompt: &str) -> Option<(String, String)> {
+    let pdf_path = looks_like_pdf_path(prompt)?;
+    let path = Path::new(pdf_path);
+    if !path.exists() {
+        return None;
+    }
+    let text = extract_text(path).ok()?;
+    if text.is_empty() {
+        return None;
+    }
+    Some((pdf_path.to_string(), text))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    /// Build a minimal valid PDF with a single page containing uncompressed
+    /// text.  This is the smallest PDF structure that exercises the BT/ET
+    /// extraction path.
+    fn build_simple_pdf(text: &str) -> Vec<u8> {
+        let content_stream = format!("BT\n/F1 12 Tf\n({text}) Tj\nET");
+        let stream_bytes = content_stream.as_bytes();
+        let mut pdf = Vec::new();
+
+        // Header
+        pdf.extend_from_slice(b"%PDF-1.4\n");
+
+        // Object 1 — Catalog
+        let obj1_offset = pdf.len();
+        pdf.extend_from_slice(b"1 0 obj\n<< /Type /Catalog /Pages 2 0 R >>\nendobj\n");
+
+        // Object 2 — Pages
+        let obj2_offset = pdf.len();
+        pdf.extend_from_slice(b"2 0 obj\n<< /Type /Pages /Kids [3 0 R] /Count 1 >>\nendobj\n");
+
+        // Object 3 — Page
+        let obj3_offset = pdf.len();
+        pdf.extend_from_slice(
+            b"3 0 obj\n<< /Type /Page /Parent 2 0 R /Contents 4 0 R >>\nendobj\n",
+        );
+
+        // Object 4 — Content stream (uncompressed)
+        let obj4_offset = pdf.len();
+        let length = stream_bytes.len();
+        let header = format!("4 0 obj\n<< /Length {length} >>\nstream\n");
+        pdf.extend_from_slice(header.as_bytes());
+        pdf.extend_from_slice(stream_bytes);
+        pdf.extend_from_slice(b"\nendstream\nendobj\n");
+
+        // Cross-reference table
+        let xref_offset = pdf.len();
+        pdf.extend_from_slice(b"xref\n0 5\n");
+        pdf.extend_from_slice(b"0000000000 65535 f \n");
+        pdf.extend_from_slice(format!("{obj1_offset:010} 00000 n \n").as_bytes());
+        pdf.extend_from_slice(format!("{obj2_offset:010} 00000 n \n").as_bytes());
+        pdf.extend_from_slice(format!("{obj3_offset:010} 00000 n \n").as_bytes());
+        pdf.extend_from_slice(format!("{obj4_offset:010} 00000 n \n").as_bytes());
+
+        // Trailer
+        pdf.extend_from_slice(b"trailer\n<< /Size 5 /Root 1 0 R >>\n");
+        pdf.extend_from_slice(format!("startxref\n{xref_offset}\n%%EOF\n").as_bytes());
+
+        pdf
+    }
+
+    /// Build a minimal PDF with flate-compressed content stream.
+    fn build_flate_pdf(text: &str) -> Vec<u8> {
+        use flate2::write::ZlibEncoder;
+        use flate2::Compression;
+        use std::io::Write as _;
+
+        let content_stream = format!("BT\n/F1 12 Tf\n({text}) Tj\nET");
+        let mut encoder = ZlibEncoder::new(Vec::new(), Compression::default());
+        encoder
+            .write_all(content_stream.as_bytes())
+            .expect("compress");
+        let compressed = encoder.finish().expect("finish");
+
+        let mut pdf = Vec::new();
+        pdf.extend_from_slice(b"%PDF-1.4\n");
+
+        let obj1_offset = pdf.len();
+        pdf.extend_from_slice(b"1 0 obj\n<< /Type /Catalog /Pages 2 0 R >>\nendobj\n");
+
+        let obj2_offset = pdf.len();
+        pdf.extend_from_slice(b"2 0 obj\n<< /Type /Pages /Kids [3 0 R] /Count 1 >>\nendobj\n");
+
+        let obj3_offset = pdf.len();
+        pdf.extend_from_slice(
+            b"3 0 obj\n<< /Type /Page /Parent 2 0 R /Contents 4 0 R >>\nendobj\n",
+        );
+
+        let obj4_offset = pdf.len();
+        let length = compressed.len();
+        let header = format!("4 0 obj\n<< /Length {length} /Filter /FlateDecode >>\nstream\n");
+        pdf.extend_from_slice(header.as_bytes());
+        pdf.extend_from_slice(&compressed);
+        pdf.extend_from_slice(b"\nendstream\nendobj\n");
+
+        let xref_offset = pdf.len();
+        pdf.extend_from_slice(b"xref\n0 5\n");
+        pdf.extend_from_slice(b"0000000000 65535 f \n");
+        pdf.extend_from_slice(format!("{obj1_offset:010} 00000 n \n").as_bytes());
+        pdf.extend_from_slice(format!("{obj2_offset:010} 00000 n \n").as_bytes());
+        pdf.extend_from_slice(format!("{obj3_offset:010} 00000 n \n").as_bytes());
+        pdf.extend_from_slice(format!("{obj4_offset:010} 00000 n \n").as_bytes());
+
+        pdf.extend_from_slice(b"trailer\n<< /Size 5 /Root 1 0 R >>\n");
+        pdf.extend_from_slice(format!("startxref\n{xref_offset}\n%%EOF\n").as_bytes());
+
+        pdf
+    }
+
+    #[test]
+    fn extracts_uncompressed_text_from_minimal_pdf() {
+        // given
+        let pdf_bytes = build_simple_pdf("Hello World");
+
+        // when
+        let text = extract_text_from_bytes(&pdf_bytes);
+
+        // then
+        assert_eq!(text, "Hello World");
+    }
+
+    #[test]
+    fn extracts_text_from_flate_compressed_stream() {
+        // given
+        let pdf_bytes = build_flate_pdf("Compressed PDF Text");
+
+        // when
+        let text = extract_text_from_bytes(&pdf_bytes);
+
+        // then
+        assert_eq!(text, "Compressed PDF Text");
+    }
+
+    #[test]
+    fn handles_tj_array_operator() {
+        // given
+        let stream = b"BT\n/F1 12 Tf\n[ (Hello) -120 ( World) ] TJ\nET";
+        // Build a raw PDF with TJ array operator instead of simple Tj.
+        let content_stream = std::str::from_utf8(stream).unwrap();
+        let raw = format!(
+            "%PDF-1.4\n1 0 obj\n<< /Type /Catalog >>\nendobj\n\
+             2 0 obj\n<< /Length {} >>\nstream\n{}\nendstream\nendobj\n%%EOF\n",
+            content_stream.len(),
+            content_stream
+        );
+        let pdf_bytes = raw.into_bytes();
+
+        // when
+        let text = extract_text_from_bytes(&pdf_bytes);
+
+        // then
+        assert_eq!(text, "Hello World");
+    }
+
+    #[test]
+    fn handles_escaped_parentheses() {
+        // given
+        let content = b"BT\n(Hello \\(World\\)) Tj\nET";
+        let raw = format!(
+            "%PDF-1.4\n1 0 obj\n<< /Length {} >>\nstream\n",
+            content.len()
+        );
+        let mut pdf_bytes = raw.into_bytes();
+        pdf_bytes.extend_from_slice(content);
+        pdf_bytes.extend_from_slice(b"\nendstream\nendobj\n%%EOF\n");
+
+        // when
+        let text = extract_text_from_bytes(&pdf_bytes);
+
+        // then
+        assert_eq!(text, "Hello (World)");
+    }
+
+    #[test]
+    fn returns_empty_for_non_pdf_data() {
+        // given
+        let data = b"This is not a PDF file at all";
+
+        // when
+        let text = extract_text_from_bytes(data);
+
+        // then
+        assert!(text.is_empty());
+    }
+
+    #[test]
+    fn extracts_text_from_file_on_disk() {
+        // given
+        let pdf_bytes = build_simple_pdf("Disk Test");
+        let dir = std::env::temp_dir().join("clawd-pdf-extract-test");
+        std::fs::create_dir_all(&dir).unwrap();
+        let pdf_path = dir.join("test.pdf");
+        std::fs::write(&pdf_path, &pdf_bytes).unwrap();
+
+        // when
+        let text = extract_text(&pdf_path).unwrap();
+
+        // then
+        assert_eq!(text, "Disk Test");
+
+        // cleanup
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+
+    #[test]
+    fn looks_like_pdf_path_detects_pdf_references() {
+        // given / when / then
+        assert_eq!(
+            looks_like_pdf_path("Please read /tmp/report.pdf"),
+            Some("/tmp/report.pdf")
+        );
+        assert_eq!(looks_like_pdf_path("Check file.PDF now"), Some("file.PDF"));
+        assert_eq!(looks_like_pdf_path("no pdf here"), None);
+    }
+
+    #[test]
+    fn maybe_extract_pdf_from_prompt_returns_none_for_missing_file() {
+        // given
+        let prompt = "Read /tmp/nonexistent-abc123.pdf please";
+
+        // when
+        let result = maybe_extract_pdf_from_prompt(prompt);
+
+        // then
+        assert!(result.is_none());
+    }
+
+    #[test]
+    fn maybe_extract_pdf_from_prompt_extracts_existing_file() {
+        // given
+        let pdf_bytes = build_simple_pdf("Auto Extracted");
+        let dir = std::env::temp_dir().join("clawd-pdf-auto-extract-test");
+        std::fs::create_dir_all(&dir).unwrap();
+        let pdf_path = dir.join("auto.pdf");
+        std::fs::write(&pdf_path, &pdf_bytes).unwrap();
+        let prompt = format!("Summarize {}", pdf_path.display());
+
+        // when
+        let result = maybe_extract_pdf_from_prompt(&prompt);
+
+        // then
+        let (path, text) = result.expect("should extract");
+        assert_eq!(path, pdf_path.display().to_string());
+        assert_eq!(text, "Auto Extracted");
+
+        // cleanup
+        let _ = std::fs::remove_dir_all(&dir);
+    }
+}